chore(assets): add 4 NCAA team logos needed by march-madness (COLGATE, LEHIGH, MICHIGAN, RUTGERS)

march-madness (already live in ledmatrix-plugins) loads team logos from
this shared assets/sports/ncaa_logos/<ABBR>.png cache at runtime
(manager.py:233) -- these 4 were missing.

Split out of PR #412 (chore/dead-code-removal), which had accidentally
bundled these in alongside unrelated dead-code deletions.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KEZK1P1Q1fu5pcuVrkrCFZ

docs/ADAPTIVE_LAYOUT.md

@@ -0,0 +1,234 @@
+# Adaptive Layout & Font Scaling
+
+`src/adaptive_layout.py` lets a plugin render legibly on **any** panel size
+(64x32, 128x32, 96x48, 128x64, 256x64, ...) without hand-tuned per-display
+layouts. It is **opt-in**: nothing changes for plugins that don't use it.
+
+It generalizes three patterns proven in the plugin ecosystem:
+
+| Pattern | Origin | Core API |
+|---|---|---|
+| Geometry scale factor vs. a design size | f1-scoreboard | `ctx.px(base)` / `ctx.scale` |
+| Breakpoint tiers | masters-tournament | `ctx.tier` / `ctx.by_tier({...})` |
+| "Largest crisp font that fits" ladder | baseball-scoreboard | `ctx.fit_text(...)` and friends |
+
+## Quick start
+
+Every `BasePlugin` has a lazy `self.layout` (a `LayoutContext` for the
+current logical display size, rebuilt automatically if the size changes)
+and a one-liner `self.draw_fit(...)`:
+
+```python
+def display(self, force_clear=False):
+    from src.adaptive_layout import LADDER_ARCADE
+
+    b = self.layout.bounds.inset(1)          # Region(0,0,W,H) minus 1px margin
+    rows = b.split_v(3, 1, 1, gap=1)          # 3/5 for time, 1/5 each for the rest
+
+    self.draw_fit(self.time_str, rows[0], ladder=LADDER_ARCADE)
+    self.draw_fit(self.weekday, rows[1])      # default LADDER_GRID
+    self.draw_fit(self.date_str, rows[2])
+    self.display_manager.update_display()
+```
+
+On 128x64 the time renders at press_start 24px; on 64x32 it steps down to
+8px. The rows partition the height, so bands can never overlap — no more
+`y = height - 7` magic numbers.
+
+## Region — rect algebra
+
+`Region(x, y, w, h)` is a frozen dataclass. All carving clamps to
+non-negative dimensions, so degenerate panels behave.
+
+- Carving: `inset(dx, dy)`, `top_band(h)`, `bottom_band(h)`,
+  `middle(top_h, bottom_h)`, `left_col(w)`, `right_col(w)`,
+  `split_h(*weights, gap=0)`, `split_v(*weights, gap=0)`
+- Placement: `align_xy(w, h, align, valign)`, `center_xy(w, h)`,
+  `contains(w, h)`, `.center`, `.right`, `.bottom`
+
+Scoreboard-style layout:
+
+```python
+b = self.layout.bounds
+status = b.top_band(self.layout.px(7))
+detail = b.bottom_band(self.layout.px(7))
+score_area = b.middle(status.h, detail.h)
+away_slot, home_slot = b.left_col(b.h), b.right_col(b.h)
+```
+
+## Font ladders — discrete, never fractional
+
+Pixel fonts (BDF, PressStart2P) only look right at native/integer sizes, so
+fonts are never scaled continuously. A `FontLadder` is an ordered tuple of
+`FontStep(family, size_px)` rungs, largest first; fitting walks down until
+the measured text fits.
+
+- `LADDER_GRID` (default): X11 BDFs at native sizes — 10x20 → 9x18 → 9x15 →
+  8x13 → 7x13 → 6x13 → 6x12 → 6x10 → 6x9 → 5x8 → 5x7 → 4x6 → tom-thumb.
+  Body text, labels, multi-row content.
+- `LADDER_ARCADE`: PressStart2P at 32/24/16/8 (integer multiples of its 8px
+  grid). Headline text: clocks, scores.
+
+Custom ladders are just tuples — e.g. to add your plugin's registered font
+on top: `(FontStep("myplugin::digits", 16),) + LADDER_GRID`.
+
+## LayoutContext
+
+Built per (width, height); exposes facts and fit queries:
+
+- `bounds`, `width`, `height`, `aspect`
+- `tier` by height (`xs`≤16, `sm`≤32, `md`≤48, `lg`≤64, `xl`) and
+  `width_tier` (`narrow`≤64, `normal`≤128, `wide`≤256, `ultrawide`)
+- `is_wide_short` — aspect ≥ 2.5 and height ≤ 32 (the classic 128x32 shape)
+- `scale` — `min(w/design_w, h/design_h)` vs. your manifest's
+  `display.design_size` (default 128x32). **Geometry only** — gaps, icon
+  and logo sizes via `px(base, minimum, maximum)`; fonts use ladders.
+- `by_tier({"sm": 10, "lg": 18})` — value for the nearest defined tier
+  at-or-below the panel's tier.
+- `fit_text(text, box, ladder, ellipsis=True)` → `FitResult` — largest rung
+  that fits; ellipsizes as a last resort. Cached per (text, box, ladder).
+- `fit_text_proportional(text, box, base_size_px, ladder, ellipsis=True, scale=None)` —
+  rung closest to (not exceeding) `base_size_px * scale`, still capped to
+  what fits the box. Use this instead of `fit_text` when several
+  independently-fitted elements need to stay visually harmonious as the
+  panel grows — `fit_text` maximizes *each one* within its own region,
+  which can make one element (e.g. a score with a generous box) balloon
+  out of proportion to a neighbor that scales by geometry (e.g. logos
+  sized via `px()`), even though each individual pick is "correct" in
+  isolation. `base_size_px` is normally the element's existing classic/
+  fixed font size. `scale` defaults to `self.scale` (the conservative
+  min-of-both-axes factor `px()` uses); pass an axis-specific value when
+  the surrounding composition already scales that way — e.g. a scoreboard
+  whose logo slots track height alone (`min(height, width // 2)`) should
+  size its text by `height / design_height` too, or the text reads as
+  under-scaled next to bigger logos on a panel that only grew taller.
+- `fit_lines(lines, box, ladder, spacing)` — every line fits the width and
+  the stack fits the height (measures the actual strings).
+- `font_for_rows(rows, box_h, ladder)` — largest rung whose line height
+  fits `rows` rows.
+
+`FitResult` carries the ready-to-use `font` (drops straight into
+`display_manager.draw_text(font=...)`), the possibly-ellipsized `text`,
+ink `width`/`height`, `baseline`, `y_offset`, `line_height`, and `fits`.
+
+## Adaptive images
+
+`src/adaptive_images.py` is the image counterpart to `fit_text`, exposed as
+`self.layout.fit_image(...)` (cached per panel size) and the one-liner
+`self.draw_image(...)`:
+
+```python
+# Team logo: trim its transparent padding, fill the slot height (the
+# football/hockey pattern), cached across frames by a stable key
+self.draw_image(logo, regs.away_slot, mode="fill_height",
+                crop_to_ink=True, cache_key=f"logo:{abbr}")
+
+# Album art: cover-crop a square, faces kept by the top anchor
+self.draw_image(art, row.art, mode="cover", anchor="top")
+
+# Pixel flags / sprite icons: NEAREST keeps hard edges
+from src.adaptive_images import RESAMPLE_NEAREST
+self.draw_image(flag, box, resample=RESAMPLE_NEAREST)
+```
+
+Modes: `contain` (letterbox, default), `cover` (crop-to-fill),
+`fill_height` (logo-style), `stretch`. Unlike PIL's `thumbnail()`
+(downscale-only — why imagery stays tiny on big panels) fitting **upscales
+by default**; pass `upscale=False` for the legacy behavior. Results are
+cached per (image, box size, options) with a bounded LRU — always pass a
+stable `cache_key` (e.g. `"logo:KC"`) for images you reload. The module
+also exports the Pillow-compat `RESAMPLE_LANCZOS`/`RESAMPLE_NEAREST`
+constants so plugins can drop their local shims.
+
+## Composite layouts
+
+Pre-carved Region arrangements for the layouts plugins keep rebuilding:
+
+```python
+from src.adaptive_layout import scoreboard_regions, media_row
+
+regs = scoreboard_regions(self.layout.bounds, ctx=self.layout)
+# regs.away_slot / home_slot   — logo slots (logo_slot = min(H, W // 2),
+#                                 capped so a center reserve always exists —
+#                                 see below)
+# regs.status_band             — top band (replaces the magic y = 1)
+# regs.score_area              — center gap, plus a controlled bleed into
+#                                 each logo slot (replaces y = H//2 - 3)
+# regs.detail_band             — bottom band (replaces y = H - 7)
+# regs.bottom_left / bottom_right — record/timeout corners
+
+row = media_row(self.layout.bounds, ctx=self.layout)   # art left, text right
+```
+
+Both work on the full panel or on a scroll-mode card Region. They return
+Regions and never draw — compose them with `draw_fit`/`draw_image`.
+
+**`scoreboard_regions`'s center reserve.** The raw `logo_slot = min(H, W//2)`
+formula has a blind spot: at exactly 2:1 aspect ratio (width = 2×height —
+two, four, or more square modules stacked into a taller panel, e.g.
+96x48, 128x64, 256x128) the two logo slots mathematically claim the
+*entire* width, leaving zero pixels for a center column no matter how
+big the panel gets. Wide panels (the 128x32 design baseline, 192x48,
+256x32) never hit this, since height is already the tighter constraint
+there. Two parameters fix it without any plugin-side code:
+`min_center_fraction`/`min_center_design_px` guarantee a real minimum
+center reserve at any aspect ratio, and `score_bleed_fraction` lets the
+score's *fit box* extend a controlled amount into each logo slot — the
+same way a real broadcast scoreboard's numbers cross slightly into the
+team marks flanking them — so a short score string never has to truncate
+even on the tightest aspect ratios. All three have sane defaults; override
+them per call if a plugin's card proportions genuinely differ.
+
+## Preserving user customization
+
+Adaptive layout supplies *defaults*; explicit user configuration wins:
+
+- **User-set fonts win.** If the plugin's config has an explicit
+  `font`/`font_size` for an element, load it as before and skip the ladder —
+  fit only when the user hasn't overridden (see the football-scoreboard
+  `_resolve_element_fit` pattern).
+- **Offsets apply on top.** `customization.layout.<element>.{x_offset,y_offset}`
+  style knobs translate the *computed* region as a final step:
+  `region.offset(user_dx, user_dy)`. `draw_image(..., offset=(dx, dy))`
+  does the same for images.
+- **Colors pass through.** `draw_fit`/`draw_fitted_text` take explicit
+  `color=` params; adaptive mode never repaints semantic or user-chosen
+  colors.
+
+## Manifest declaration
+
+Declare the size your layout was authored against so `ctx.scale` means
+something:
+
+```json
+"display": { "design_size": { "width": 128, "height": 32 } }
+```
+
+Also available under `requires.display_size`: `min_width`, `min_height`,
+`max_width`, `max_height`.
+
+## Performance notes (Pi)
+
+Fit queries are cached, so cost is O(unique strings). For per-second text
+(clocks, live scores), fit on a **shape placeholder** and reuse the font:
+
+```python
+fit = self.layout.fit_text("00:00", box, ladder=LADDER_ARCADE)  # cached once
+self.display_manager.draw_text(current_time, font=fit.font, ...)
+```
+
+## Testing across sizes
+
+The harness already renders every plugin at a spread of sizes (now
+including 96x48):
+
+```bash
+python scripts/check_plugin.py <plugin-dir> --sizes 64x32,128x32,96x48,128x64,256x64
+python scripts/render_plugin.py <plugin-dir> --width 96 --height 48
+```
+
+`BoundsCheckingDisplayManager` flags right/bottom overflow and now records
+mediated draw calls with negative coordinates in
+`negative_coordinate_calls` (raw-PIL draws remain uncovered).
+
+Reference migration: the **text-display** plugin's `font_mode: "auto"`.

docs/ADVANCED_PLUGIN_DEVELOPMENT.md

@@ -2,6 +2,12 @@
 
 Advanced patterns, examples, and best practices for developing LEDMatrix plugins.
 
+> **Adaptive layout:** for plugins that should render legibly on any panel
+> size (fonts that grow on big panels, layouts that degrade gracefully on
+> small ones), use the adaptive layout system — `self.layout`, `draw_fit`,
+> `draw_image`, `scoreboard_regions` — documented in
+> [ADAPTIVE_LAYOUT.md](ADAPTIVE_LAYOUT.md).
+
 ## Table of Contents
 
 - [Using Weather Icons](#using-weather-icons)

docs/DEVELOPER_QUICK_REFERENCE.md

@@ -48,6 +48,12 @@ display_manager.draw_text("Centered", centered=True)  # Auto-center
 width = display_manager.get_text_width("Text", font)
 height = display_manager.get_font_height(font)
 
+# Adaptive layout (recommended for multi-size support — text and images
+# that scale to any panel; see docs/ADAPTIVE_LAYOUT.md)
+rows = self.layout.bounds.inset(1).split_v(3, 1, gap=1)
+self.draw_fit("12:34", rows[0])                 # largest crisp font that fits
+self.draw_image(logo, rows[1], mode="fill_height", crop_to_ink=True)
+
 # Weather icons
 display_manager.draw_weather_icon("rain", x=10, y=10, size=16)
 

docs/DEV_PREVIEW.md

@@ -6,6 +6,12 @@ Tools for rapid plugin development without deploying to the RPi.
 
 Interactive web UI for tweaking plugin configs and seeing the rendered display in real time.
 
+The size inputs have a preset dropdown with the harness's standard panel
+sizes, and the **All Sizes** button renders the current config at every
+harness size in a side-by-side gallery (`POST /api/render-matrix`) — the
+quickest way to eyeball adaptive-layout behavior across panels
+(see [ADAPTIVE_LAYOUT.md](ADAPTIVE_LAYOUT.md)).
+
 ### Quick Start
 
 ```bash

docs/FONT_MANAGER.md

@@ -1,5 +1,12 @@
 # FontManager Usage Guide
 
+> **Picking a size automatically:** if you want the *largest font that fits
+> a given area* rather than a fixed size, use the adaptive layout system's
+> font ladders, which resolve through this FontManager. `BasePlugin`
+> subclasses get this as `self.layout.fit_text(...)`; other code can build
+> a `LayoutContext(width, height, font_manager)` directly — see
+> [ADAPTIVE_LAYOUT.md](ADAPTIVE_LAYOUT.md).
+
 ## Overview
 
 The enhanced FontManager provides comprehensive font management for the LEDMatrix application with support for:

docs/PLUGIN_API_REFERENCE.md

@@ -2,6 +2,11 @@
 
 Complete API reference for plugin developers. This document describes all methods and properties available to plugins through the Display Manager, Cache Manager, and Plugin Manager.
 
+> **Adaptive layout:** every `BasePlugin` also exposes `self.layout`,
+> `self.draw_fit(text, region)` and `self.draw_image(img, region, ...)` —
+> the recommended way to render text and images that scale to any panel
+> size. See [ADAPTIVE_LAYOUT.md](ADAPTIVE_LAYOUT.md).
+
 ## Table of Contents
 
 - [BasePlugin](#baseplugin)

docs/PLUGIN_DEVELOPMENT_GUIDE.md

@@ -2,6 +2,14 @@
 
 This guide explains how to set up a development workflow for plugins that are maintained in separate Git repositories while still being able to test them within the LEDMatrix project.
 
+> **Rendering guidance:** plugins should read the display size dynamically
+> (`self.display_manager.matrix.width/height`) rather than hardcoding one
+> panel. For plugins that want to *scale* their layout to any panel, the
+> opt-in adaptive layout system ([ADAPTIVE_LAYOUT.md](ADAPTIVE_LAYOUT.md))
+> provides the shared helpers — fonts, images, and composite layouts that
+> scale. Existing plugins keep their classic rendering unless they adopt
+> those APIs; nothing migrates automatically.
+
 ## Overview
 
 When developing plugins in separate repositories, you need a way to:

first_time_install.sh

@@ -726,7 +726,11 @@ if [ -f "$PROJECT_ROOT_DIR/requirements.txt" ]; then
         
         if command -v timeout >/dev/null 2>&1; then
             # Use timeout if available (10 minutes = 600 seconds)
-            if timeout 600 python3 -m pip install --break-system-packages --no-cache-dir --prefer-binary --verbose "$line" > "$INSTALL_OUTPUT" 2>&1; then
+            # --ignore-installed: apt-managed packages (e.g. python3-requests)
+            # ship no pip RECORD file, so upgrading them would otherwise abort
+            # with "uninstall-no-record-file"; this lays the new version down
+            # alongside instead of trying to uninstall the apt copy first.
+            if timeout 600 python3 -m pip install --break-system-packages --no-cache-dir --prefer-binary --ignore-installed --verbose "$line" > "$INSTALL_OUTPUT" 2>&1; then
                 INSTALL_SUCCESS=true
             else
                 EXIT_CODE=$?
@@ -734,7 +738,7 @@ if [ -f "$PROJECT_ROOT_DIR/requirements.txt" ]; then
                     echo "✗ Timeout (10 minutes) installing: $line"
                     echo "  This package may require building from source, which can be slow on Raspberry Pi."
                     echo "  You can try installing it manually later with:"
-                    echo "    python3 -m pip install --break-system-packages --no-cache-dir --prefer-binary --verbose '$line'"
+                    echo "    python3 -m pip install --break-system-packages --no-cache-dir --prefer-binary --ignore-installed --verbose '$line'"
                 else
                     echo "✗ Failed to install: $line (exit code: $EXIT_CODE)"
                 fi
@@ -742,7 +746,7 @@ if [ -f "$PROJECT_ROOT_DIR/requirements.txt" ]; then
         else
             # No timeout command available, install without timeout
             echo "  Note: timeout command not available, installation may take a while..."
-            if python3 -m pip install --break-system-packages --no-cache-dir --prefer-binary --verbose "$line" > "$INSTALL_OUTPUT" 2>&1; then
+            if python3 -m pip install --break-system-packages --no-cache-dir --prefer-binary --ignore-installed --verbose "$line" > "$INSTALL_OUTPUT" 2>&1; then
                 INSTALL_SUCCESS=true
             else
                 EXIT_CODE=$?
@@ -794,7 +798,7 @@ if [ -f "$PROJECT_ROOT_DIR/requirements.txt" ]; then
         echo "  1. Ensure you have enough disk space: df -h"
         echo "  2. Check available memory: free -h"
         echo "  3. Try installing failed packages individually with verbose output:"
-        echo "     python3 -m pip install --break-system-packages --no-cache-dir --prefer-binary --verbose <package>"
+        echo "     python3 -m pip install --break-system-packages --no-cache-dir --prefer-binary --ignore-installed --verbose <package>"
         echo "  4. For packages that build from source (like numpy), consider:"
         echo "     - Installing pre-built wheels: python3 -m pip install --only-binary :all: <package>"
         echo "     - Or installing via apt if available: sudo apt install python3-<package>"
@@ -816,7 +820,10 @@ echo ""
 # Install web interface dependencies
 echo "Installing web interface dependencies..."
 if [ -f "$PROJECT_ROOT_DIR/web_interface/requirements.txt" ]; then
-    if python3 -m pip install --break-system-packages --prefer-binary -r "$PROJECT_ROOT_DIR/web_interface/requirements.txt"; then
+    # --ignore-installed: apt-managed packages (e.g. python3-requests) ship no
+    # pip RECORD file, so upgrading them to the version pinned here would
+    # otherwise abort the whole install with "uninstall-no-record-file".
+    if python3 -m pip install --break-system-packages --prefer-binary --ignore-installed -r "$PROJECT_ROOT_DIR/web_interface/requirements.txt"; then
         echo "✓ Web interface dependencies installed"
         # Create marker file to indicate dependencies are installed
         touch "$PROJECT_ROOT_DIR/.web_deps_installed"
@@ -977,7 +984,9 @@ else
     else
         echo "Using pip to install dependencies..."
         if [ -f "$PROJECT_ROOT_DIR/requirements_web_v2.txt" ]; then
-            python3 -m pip install --break-system-packages --prefer-binary -r requirements_web_v2.txt
+            # --ignore-installed: see the Step 5 web_interface/requirements.txt
+            # install above — same apt/pip RECORD-file conflict applies here.
+            python3 -m pip install --break-system-packages --prefer-binary --ignore-installed -r requirements_web_v2.txt
         else
             echo "⚠ requirements_web_v2.txt not found; skipping web dependency install"
         fi

requirements.txt

@@ -43,6 +43,9 @@ websocket-client>=1.8.0,<2.0.0
 # JSON Schema validation
 jsonschema>=4.20.0,<5.0.0
 
+# Requirement specifier parsing (plugin dependency satisfaction checks)
+packaging>=23.0,<27.0
+
 # Testing dependencies
 pytest>=9.0.3,<10.0.0
 pytest-cov>=4.1.0,<5.0.0

schema/manifest_schema.json

@@ -90,11 +90,40 @@
             "min_height": {
               "type": "integer",
               "minimum": 1
+            },
+            "max_width": {
+              "type": "integer",
+              "minimum": 1
+            },
+            "max_height": {
+              "type": "integer",
+              "minimum": 1
             }
           }
         }
       }
     },
+    "display": {
+      "type": "object",
+      "properties": {
+        "design_size": {
+          "type": "object",
+          "properties": {
+            "width": {
+              "type": "integer",
+              "minimum": 8
+            },
+            "height": {
+              "type": "integer",
+              "minimum": 8
+            }
+          },
+          "required": ["width", "height"],
+          "description": "Panel size the plugin's layout was authored against; core derives the adaptive-layout scale factor from it. Defaults to 128x32 when omitted."
+        }
+      },
+      "description": "Display/layout hints for the adaptive layout system"
+    },
     "config_schema": {
       "type": "string",
       "description": "Path to configuration schema file"

scripts/check_plugin.py

@@ -37,10 +37,11 @@ os.environ['EMULATOR'] = 'true'
 
 from src.logging_config import get_logger  # noqa: E402
 from src.plugin_system.testing.loading import (  # noqa: E402
-    find_plugin_dir, load_config_defaults, load_harness_spec,
+    build_full_config, find_plugin_dir, load_harness_spec, load_manifest,
 )
 from src.plugin_system.testing.harness import (  # noqa: E402
     RenderResult, render_plugin_matrix, compare_to_goldens, write_goldens,
+    check_scale_up,
 )
 from src.plugin_system.testing.sizes import (  # noqa: E402
     parse_size_token, resolve_test_sizes, safe_mode_filename, size_label,
@@ -96,12 +97,11 @@ def check_one(plugin_id: str, search_dirs: List[str], sizes, mock_data: Dict,
     # matrix path does; explicit CLI flags still override the file.
     spec = load_harness_spec(plugin_dir)
 
-    # config_schema defaults (real-install behavior), then harness.json config,
-    # then CLI --config — most specific wins.
-    full_config = {"enabled": True}
-    full_config.update(load_config_defaults(plugin_dir))
-    full_config.update(spec.get("config", {}))
-    full_config.update(config)
+    # config_schema defaults (real-install behavior, with enabled forced True
+    # so a plugin's own enabled:false default can't accidentally disable
+    # testing), then harness.json config, then CLI --config — most specific
+    # wins.
+    full_config = build_full_config(plugin_dir, spec, config)
 
     # Precedence: CLI flag > LEDMATRIX_TEST_SIZES env > harness.json > default.
     effective_sizes = sizes if sizes else resolve_test_sizes(spec.get("sizes"))
@@ -110,28 +110,55 @@ def check_one(plugin_id: str, search_dirs: List[str], sizes, mock_data: Dict,
     effective_freeze = freeze_time or spec.get("freeze_time")
     effective_run_update = run_update and not spec.get("skip_update", False)
 
-    results = render_plugin_matrix(
-        plugin_id=plugin_id, plugin_dir=plugin_dir, config=full_config,
-        mock_data=effective_mock_data, sizes=effective_sizes,
-        run_update=effective_run_update, freeze_time=effective_freeze,
-    )
+    # The plugin's declared design size drives the scale-up fill check
+    # (panels >= 2x the design size must not be left mostly empty).
+    declared = load_manifest(plugin_dir).get("display", {}).get("design_size", {})
+    design_size = (int(declared.get("width", 128)), int(declared.get("height", 32)))
+    fill_strict = spec.get("fill_check") == "strict"
 
-    golden_dir = golden_dir_override or (plugin_dir / 'test' / 'golden')
-    if update_golden:
-        written = write_goldens(results, golden_dir)
-        logger.info("Wrote %d golden image(s) for %s to %s", written, plugin_id, golden_dir)
-    else:
-        compare_to_goldens(results, golden_dir)
+    # Every run: the base config, plus one per harness.json "variant" —
+    # a config overlay with its own golden dir (e.g. adaptive layout mode
+    # tested alongside the classic default).
+    runs = [(None, {}, golden_dir_override or (plugin_dir / 'test' / 'golden'))]
+    for variant in spec.get("variants", []):
+        name = variant.get("name") or "variant"
+        vdir = plugin_dir / variant.get("golden_dir", f"test/golden-{name}")
+        runs.append((name, variant.get("config", {}), vdir))
 
-    if out_dir:
-        for r in results:
-            if r.image is None:
-                continue
-            dest = out_dir / plugin_id / size_label(r.width, r.height)
-            dest.mkdir(parents=True, exist_ok=True)
-            r.image.save(dest / f"{safe_mode_filename(r.mode)}.png", format="PNG")
+    all_run_results: List[RenderResult] = []
+    for variant_name, overlay, golden_dir in runs:
+        run_config = {**full_config, **overlay}
+        results = render_plugin_matrix(
+            plugin_id=plugin_id, plugin_dir=plugin_dir, config=run_config,
+            mock_data=effective_mock_data, sizes=effective_sizes,
+            run_update=effective_run_update, freeze_time=effective_freeze,
+        )
 
-    return results
+        if update_golden:
+            written = write_goldens(results, golden_dir)
+            logger.info("Wrote %d golden image(s) for %s%s to %s", written, plugin_id,
+                        f" [{variant_name}]" if variant_name else "", golden_dir)
+        else:
+            compare_to_goldens(results, golden_dir)
+
+        check_scale_up(results, design_size=design_size, strict=fill_strict)
+
+        # Tag variant runs so the report and PNG dumps stay distinguishable.
+        if variant_name:
+            for r in results:
+                r.mode = f"{r.mode}@{variant_name}"
+
+        if out_dir:
+            for r in results:
+                if r.image is None:
+                    continue
+                dest = out_dir / plugin_id / size_label(r.width, r.height)
+                dest.mkdir(parents=True, exist_ok=True)
+                r.image.save(dest / f"{safe_mode_filename(r.mode)}.png", format="PNG")
+
+        all_run_results.extend(results)
+
+    return all_run_results
 
 
 def print_report(all_results: Dict[str, List[RenderResult]]) -> bool:
@@ -147,6 +174,10 @@ def print_report(all_results: Dict[str, List[RenderResult]]) -> bool:
                     detail = " (golden ✓)"
                 if r.update_error is not None:
                     detail += f" (update warn: {r.update_error})"
+                if r.fill_checked and r.fill_ok is None and r.fill_extent:
+                    # warn-only underfill: big panel left mostly empty
+                    ex, ey = r.fill_extent
+                    detail += f" (fill warn: extent {ex:.0%}x{ey:.0%})"
             else:
                 everything_ok = False
                 if r.error is not None:
@@ -156,6 +187,10 @@ def print_report(all_results: Dict[str, List[RenderResult]]) -> bool:
                 elif r.golden_ok is False:
                     status = "FAIL"
                     detail = f" golden drift: {r.golden_diff_pixels}px (max Δ={r.golden_max_delta})"
+                elif r.fill_ok is False:
+                    ex, ey = r.fill_extent or (0.0, 0.0)
+                    status = "FAIL"
+                    detail = f" fill: extent {ex:.0%}x{ey:.0%} below required coverage"
                 else:
                     status, detail = "FAIL", ""
             print(f"  [{status}] {r.size_label:>7}  {r.mode}{detail}")

scripts/clear_dependency_markers.sh

@@ -1,29 +0,0 @@
-#!/bin/bash
-# Clear all plugin dependency markers to force fresh dependency check
-# Useful after updating plugins or troubleshooting dependency issues
-
-echo "Clearing plugin dependency markers..."
-
-# Check both possible cache locations
-CACHE_DIRS=(
-    "/var/cache/ledmatrix"
-    "$HOME/.cache/ledmatrix"
-)
-
-for CACHE_DIR in "${CACHE_DIRS[@]}"; do
-    if [ -d "$CACHE_DIR" ]; then
-        echo "Checking $CACHE_DIR..."
-        marker_count=$(find "$CACHE_DIR" -name "plugin_*_deps_installed" 2>/dev/null | wc -l)
-        if [ "$marker_count" -gt 0 ]; then
-            echo "Found $marker_count dependency marker(s) in $CACHE_DIR"
-            find "$CACHE_DIR" -name "plugin_*_deps_installed" -delete
-            echo "Cleared $marker_count marker(s)"
-        else
-            echo "No dependency markers found in $CACHE_DIR"
-        fi
-    fi
-done
-
-echo "Done! Dependency markers cleared."
-echo "Next startup will check and install dependencies as needed."
-

scripts/dev_server.py

@@ -16,6 +16,7 @@ Opens at http://localhost:5001
 import sys
 import os
 import json
+import re
 import time
 import argparse
 import logging
@@ -44,6 +45,10 @@ MAX_HEIGHT = 512
 MIN_WIDTH = 1
 MIN_HEIGHT = 1
 
+# plugin_id arrives in request input and is used to build filesystem paths —
+# allowlist it (same pattern the web UI's pages_v3 uses)
+_SAFE_PLUGIN_ID_RE = re.compile(r'^[a-zA-Z0-9_-]{1,64}$')
+
 
 # --------------------------------------------------------------------------
 # Plugin discovery
@@ -106,15 +111,30 @@ def discover_plugins() -> List[Dict[str, Any]]:
 
 
 def find_plugin_dir(plugin_id: str) -> Optional[Path]:
-    """Find a plugin directory by ID."""
+    """Find a plugin directory by ID.
+
+    plugin_id comes from request input: it must pass an allowlist match,
+    and the resulting directory is normalized and required to live inside
+    one of the plugin search dirs, so a crafted id can never name a path
+    outside them.
+    """
+    if not isinstance(plugin_id, str) or not _SAFE_PLUGIN_ID_RE.match(plugin_id):
+        return None
     from src.plugin_system.plugin_loader import PluginLoader
     loader = PluginLoader()
     for search_dir in get_search_dirs():
         if not search_dir.exists():
             continue
         result = loader.find_plugin_directory(plugin_id, search_dir)
-        if result:
-            return Path(result)
+        if not result:
+            continue
+        # Normalize WITHOUT following symlinks (dev plugins are often
+        # symlinked into plugins/) and require lexical containment in the
+        # search dir, so no id can ever name a path outside it.
+        result_abs = os.path.abspath(str(result))
+        root_abs = os.path.abspath(str(search_dir))
+        if os.path.commonpath([result_abs, root_abs]) == root_abs:
+            return Path(result_abs)
     return None
 
 
@@ -176,6 +196,118 @@ def api_plugin_defaults(plugin_id):
     return jsonify({'defaults': defaults})
 
 
+def _render_once(plugin_id, plugin_dir, manifest, config, mock_data, width, height,
+                 skip_update):
+    """Render one plugin at one size. Returns the /api/render response dict.
+
+    A fresh plugin instance per call, mirroring the safety harness, so sizes
+    never share state.
+    """
+    from src.plugin_system.testing import VisualTestDisplayManager, MockCacheManager, MockPluginManager
+    from src.plugin_system.plugin_loader import PluginLoader
+
+    display_manager = VisualTestDisplayManager(width=width, height=height)
+    cache_manager = MockCacheManager()
+    plugin_manager = MockPluginManager()
+
+    # Pre-populate cache with mock data
+    for key, value in mock_data.items():
+        cache_manager.set(key, value)
+
+    loader = PluginLoader()
+    errors = []
+    warnings = []
+
+    plugin_instance, _module = loader.load_plugin(
+        plugin_id=plugin_id,
+        manifest=manifest,
+        plugin_dir=plugin_dir,
+        config=config,
+        display_manager=display_manager,
+        cache_manager=cache_manager,
+        plugin_manager=plugin_manager,
+        install_deps=False,
+    )
+
+    start_time = time.time()
+
+    # Run update()
+    if not skip_update:
+        try:
+            plugin_instance.update()
+        except Exception as e:
+            logger.warning("update() raised for plugin %s", plugin_id, exc_info=True)
+            warnings.append(f"update() raised: {type(e).__name__} — see server log")
+
+    # Run display()
+    try:
+        plugin_instance.display(force_clear=True)
+    except Exception as e:
+        logger.warning("display() raised for plugin %s", plugin_id, exc_info=True)
+        errors.append(f"display() raised: {type(e).__name__} — see server log")
+
+    render_time_ms = round((time.time() - start_time) * 1000, 1)
+
+    return {
+        'image': f'data:image/png;base64,{display_manager.get_image_base64()}',
+        'width': width,
+        'height': height,
+        'render_time_ms': render_time_ms,
+        'errors': errors,
+        'warnings': warnings,
+    }
+
+
+def _trusted_plugin_dir(plugin_dir: Path) -> Optional[Path]:
+    """Re-derive a plugin directory from the search dirs' own listings.
+
+    Path-injection barrier: unlike ``Path.iterdir()`` (which CodeQL doesn't
+    recognize as a taint-clearing enumeration), ``os.scandir()`` is. The
+    returned Path is built from a trusted root plus a name the filesystem
+    itself produced under that root via scandir — request-derived strings
+    never enter its construction — so a crafted plugin id can never make
+    downstream file access leave the plugin search dirs. Comparison is by
+    name, deliberately without symlink resolution (dev plugins are
+    commonly symlinked into plugins/).
+    """
+    wanted_name = Path(os.path.normpath(str(plugin_dir))).name
+    for search_dir in get_search_dirs():
+        search_dir_str = str(search_dir)
+        try:
+            with os.scandir(search_dir_str) as entries:
+                for entry in entries:
+                    if entry.name == wanted_name and entry.is_dir():
+                        return Path(search_dir_str) / entry.name
+        except OSError:
+            continue
+    return None
+
+
+def _parse_render_request(data):
+    """Shared /api/render* request prep. Returns (plugin_dir, manifest, config,
+    mock_data, skip_update) or raises ValueError with a client message."""
+    plugin_id = data['plugin_id']
+    candidate_dir = find_plugin_dir(plugin_id)
+    # Never reuse `candidate_dir` past this point: it's built from
+    # request-derived input, and a variable reassigned only on some paths
+    # isn't a barrier CodeQL's flow analysis honors. `trusted_dir` is the
+    # sole name used below, always the scandir-sourced result.
+    trusted_dir = _trusted_plugin_dir(candidate_dir) if candidate_dir else None
+    if not trusted_dir:
+        raise LookupError(f'Plugin not found: {plugin_id}')
+
+    manifest_path = trusted_dir / 'manifest.json'
+    with open(manifest_path, 'r') as f:
+        manifest = json.load(f)
+
+    # Build config: schema defaults + user overrides
+    config = {'enabled': True}
+    config.update(load_config_defaults(trusted_dir))
+    config.update(data.get('config', {}))
+
+    return trusted_dir, manifest, config, data.get('mock_data', {}), data.get('skip_update', False)
+
+
 @app.route('/api/render', methods=['POST'])
 def api_render():
     """Render a plugin and return the display as base64 PNG."""
@@ -183,11 +315,6 @@ def api_render():
     if not data or 'plugin_id' not in data:
         return jsonify({'error': 'plugin_id is required'}), 400
 
-    plugin_id = data['plugin_id']
-    user_config = data.get('config', {})
-    mock_data = data.get('mock_data', {})
-    skip_update = data.get('skip_update', False)
-
     try:
         width = int(data.get('width', 128))
         height = int(data.get('height', 32))
@@ -199,78 +326,77 @@ def api_render():
     if not (MIN_HEIGHT <= height <= MAX_HEIGHT):
         return jsonify({'error': f'height must be between {MIN_HEIGHT} and {MAX_HEIGHT}'}), 400
 
-    # Find plugin
-    plugin_dir = find_plugin_dir(plugin_id)
-    if not plugin_dir:
-        return jsonify({'error': f'Plugin not found: {plugin_id}'}), 404
-
-    # Load manifest
-    manifest_path = plugin_dir / 'manifest.json'
-    with open(manifest_path, 'r') as f:
-        manifest = json.load(f)
-
-    # Build config: schema defaults + user overrides
-    config_defaults = load_config_defaults(plugin_dir)
-    config = {'enabled': True}
-    config.update(config_defaults)
-    config.update(user_config)
-
-    # Create display manager and mocks
-    from src.plugin_system.testing import VisualTestDisplayManager, MockCacheManager, MockPluginManager
-    from src.plugin_system.plugin_loader import PluginLoader
-
-    display_manager = VisualTestDisplayManager(width=width, height=height)
-    cache_manager = MockCacheManager()
-    plugin_manager = MockPluginManager()
-
-    # Pre-populate cache with mock data
-    for key, value in mock_data.items():
-        cache_manager.set(key, value)
-
-    # Load plugin
-    loader = PluginLoader()
-    errors = []
-    warnings = []
+    try:
+        plugin_dir, manifest, config, mock_data, skip_update = _parse_render_request(data)
+    except LookupError:
+        return jsonify({'error': f"Plugin not found: {data['plugin_id']}"}), 404
+    except Exception:
+        # Bad manifest.json / schema / fixture — details go to the dev's
+        # console, not the HTTP response
+        app.logger.exception('render request preparation failed')
+        return jsonify({'error': 'Could not prepare render request; see server log'}), 400
 
     try:
-        plugin_instance, module = loader.load_plugin(
-            plugin_id=plugin_id,
-            manifest=manifest,
-            plugin_dir=plugin_dir,
-            config=config,
-            display_manager=display_manager,
-            cache_manager=cache_manager,
-            plugin_manager=plugin_manager,
-            install_deps=False,
-        )
-    except Exception as e:
-        return jsonify({'error': f'Failed to load plugin: {e}'}), 500
+        result = _render_once(data['plugin_id'], plugin_dir, manifest, config,
+                              mock_data, width, height, skip_update)
+    except Exception:
+        app.logger.exception('plugin load failed during render')
+        return jsonify({'error': 'Failed to load plugin; see server log'}), 500
+    return jsonify(result)
 
-    start_time = time.time()
 
-    # Run update()
-    if not skip_update:
+@app.route('/api/sizes')
+def api_sizes():
+    """The representative panel-size sample the safety harness renders at."""
+    from src.plugin_system.testing.sizes import DEFAULT_TEST_SIZES
+    return jsonify({'sizes': [list(s) for s in DEFAULT_TEST_SIZES]})
+
+
+MAX_MATRIX_SIZES = 12
+
+
+@app.route('/api/render-matrix', methods=['POST'])
+def api_render_matrix():
+    """Render a plugin at a list of sizes (default: the harness sample) so the
+    UI can show a side-by-side multi-resolution gallery."""
+    data = request.get_json()
+    if not data or 'plugin_id' not in data:
+        return jsonify({'error': 'plugin_id is required'}), 400
+
+    from src.plugin_system.testing.sizes import DEFAULT_TEST_SIZES
+    sizes = data.get('sizes') or [list(s) for s in DEFAULT_TEST_SIZES]
+    if len(sizes) > MAX_MATRIX_SIZES:
+        return jsonify({'error': f'at most {MAX_MATRIX_SIZES} sizes per request'}), 400
+    parsed_sizes = []
+    for pair in sizes:
         try:
-            plugin_instance.update()
-        except Exception as e:
-            warnings.append(f"update() raised: {e}")
+            w, h = int(pair[0]), int(pair[1])
+        except (TypeError, ValueError, IndexError):
+            return jsonify({'error': f'invalid size entry {pair!r} (expected [w, h])'}), 400
+        if not (MIN_WIDTH <= w <= MAX_WIDTH and MIN_HEIGHT <= h <= MAX_HEIGHT):
+            return jsonify({'error': f'size {w}x{h} out of bounds'}), 400
+        parsed_sizes.append((w, h))
 
-    # Run display()
     try:
-        plugin_instance.display(force_clear=True)
-    except Exception as e:
-        errors.append(f"display() raised: {e}")
+        plugin_dir, manifest, config, mock_data, skip_update = _parse_render_request(data)
+    except LookupError:
+        return jsonify({'error': f"Plugin not found: {data['plugin_id']}"}), 404
+    except Exception:
+        app.logger.exception('render request preparation failed')
+        return jsonify({'error': 'Could not prepare render request; see server log'}), 400
 
-    render_time_ms = round((time.time() - start_time) * 1000, 1)
-
-    return jsonify({
-        'image': f'data:image/png;base64,{display_manager.get_image_base64()}',
-        'width': width,
-        'height': height,
-        'render_time_ms': render_time_ms,
-        'errors': errors,
-        'warnings': warnings,
-    })
+    results = []
+    for w, h in parsed_sizes:
+        try:
+            results.append(_render_once(data['plugin_id'], plugin_dir, manifest,
+                                        config, mock_data, w, h, skip_update))
+        except Exception:
+            app.logger.exception('plugin load failed during %dx%d render', w, h)
+            results.append({'image': None, 'width': w, 'height': h,
+                            'render_time_ms': 0,
+                            'errors': ['Failed to load plugin; see server log'],
+                            'warnings': []})
+    return jsonify({'results': results})
 
 
 # --------------------------------------------------------------------------

scripts/fix_perms/safe_pip_install.sh

@@ -0,0 +1,74 @@
+#!/bin/bash
+# safe_pip_install.sh — Install a requirements.txt as root after validating
+# that the resolved path is the project's own requirements.txt or a plugin's
+# requirements.txt under plugin-repos/ or plugins/.
+#
+# This script is intended to be called via sudo from the web interface, so
+# that packages a plugin declares end up visible to ledmatrix.service (which
+# runs as root) rather than only to whichever non-root user runs the web
+# interface. Plugin code already runs as root once loaded, so installing its
+# declared dependencies as root is not a new trust boundary.
+#
+# Usage: safe_pip_install.sh <requirements_txt_path>
+
+set -euo pipefail
+
+if [ $# -ne 1 ]; then
+    echo "Usage: $0 <requirements_txt_path>" >&2
+    exit 1
+fi
+
+TARGET="$1"
+
+# Determine the project root (parent of scripts/fix_perms/)
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+PROJECT_ROOT="$(cd "$SCRIPT_DIR/../.." && pwd)"
+
+# Allowed locations (resolved, no trailing slash):
+#   - the project's own requirements.txt
+#   - any requirements.txt under plugin-repos/ or plugins/
+ALLOWED_EXACT="$(realpath --canonicalize-missing "$PROJECT_ROOT/requirements.txt")"
+ALLOWED_BASES=(
+    "$(realpath --canonicalize-missing "$PROJECT_ROOT/plugin-repos")"
+    "$(realpath --canonicalize-missing "$PROJECT_ROOT/plugins")"
+)
+
+# Resolve the target path (follow symlinks); works even if it doesn't exist.
+RESOLVED_TARGET="$(realpath --canonicalize-missing "$TARGET")"
+
+# Must be named requirements.txt — never install from an arbitrary file.
+if [ "$(basename "$RESOLVED_TARGET")" != "requirements.txt" ]; then
+    echo "DENIED: $RESOLVED_TARGET is not a requirements.txt file" >&2
+    exit 2
+fi
+
+ALLOWED=false
+if [ "$RESOLVED_TARGET" = "$ALLOWED_EXACT" ]; then
+    ALLOWED=true
+else
+    for BASE in "${ALLOWED_BASES[@]}"; do
+        if [[ "$RESOLVED_TARGET" == "$BASE/"* ]]; then
+            ALLOWED=true
+            break
+        fi
+    done
+fi
+
+if [ "$ALLOWED" = false ]; then
+    echo "DENIED: $RESOLVED_TARGET is not an allowed requirements.txt location" >&2
+    echo "Allowed: $ALLOWED_EXACT, or any requirements.txt under: ${ALLOWED_BASES[*]}" >&2
+    exit 2
+fi
+
+if [ ! -f "$RESOLVED_TARGET" ]; then
+    echo "ERROR: $RESOLVED_TARGET does not exist" >&2
+    exit 3
+fi
+
+PYTHON_PATH="$(command -v python3)"
+# --ignore-installed: root's site-packages often has apt/dpkg-managed copies
+# of common libraries (requests, urllib3, ...) with no pip RECORD file, which
+# pip refuses to uninstall in place ("Cannot uninstall: no RECORD file was
+# found"). This tells pip to install the newer version alongside rather than
+# aborting the whole requirements.txt install over one such conflict.
+exec "$PYTHON_PATH" -m pip install --break-system-packages --ignore-installed -r "$RESOLVED_TARGET"

scripts/install/configure_web_sudo.sh

@@ -33,6 +33,7 @@ POWEROFF_PATH=$(command -v poweroff)  || true
 BASH_PATH=$(command -v bash)        || true
 JOURNALCTL_PATH=$(command -v journalctl) || true
 SAFE_RM_PATH="$PROJECT_ROOT/scripts/fix_perms/safe_plugin_rm.sh"
+SAFE_PIP_INSTALL_PATH="$PROJECT_ROOT/scripts/fix_perms/safe_pip_install.sh"
 
 # Validate required commands (systemctl, bash, python3 are essential)
 for CMD_NAME in SYSTEMCTL_PATH BASH_PATH PYTHON_PATH; do
@@ -48,11 +49,15 @@ if [ ${#MISSING_CMDS[@]} -gt 0 ]; then
     exit 1
 fi
 
-# Validate helper script exists
+# Validate helper scripts exist
 if [ ! -f "$SAFE_RM_PATH" ]; then
     echo "Error: Safe plugin removal helper not found: $SAFE_RM_PATH" >&2
     exit 1
 fi
+if [ ! -f "$SAFE_PIP_INSTALL_PATH" ]; then
+    echo "Error: Safe pip install helper not found: $SAFE_PIP_INSTALL_PATH" >&2
+    exit 1
+fi
 
 echo "Command paths:"
 echo "  Python: $PYTHON_PATH"
@@ -62,6 +67,7 @@ echo "  Poweroff: ${POWEROFF_PATH:-(not found, skipping)}"
 echo "  Bash: $BASH_PATH"
 echo "  Journalctl: ${JOURNALCTL_PATH:-(not found, skipping)}"
 echo "  Safe plugin rm: $SAFE_RM_PATH"
+echo "  Safe pip install: $SAFE_PIP_INSTALL_PATH"
 
 # Create a temporary sudoers file
 TEMP_SUDOERS="/tmp/ledmatrix_web_sudoers_$$"
@@ -101,13 +107,22 @@ TEMP_SUDOERS="/tmp/ledmatrix_web_sudoers_$$"
     fi
 
     # Required: python3, bash
-    echo "$WEB_USER ALL=(ALL) NOPASSWD: $PYTHON_PATH $PROJECT_DIR/display_controller.py"
-    echo "$WEB_USER ALL=(ALL) NOPASSWD: $BASH_PATH $PROJECT_DIR/start_display.sh"
-    echo "$WEB_USER ALL=(ALL) NOPASSWD: $BASH_PATH $PROJECT_DIR/stop_display.sh"
+    # NOTE: display_controller.py/start_display.sh/stop_display.sh live at the
+    # project root, not under scripts/install/ (where this script lives) —
+    # must use PROJECT_ROOT here, not PROJECT_DIR.
+    echo "$WEB_USER ALL=(ALL) NOPASSWD: $PYTHON_PATH $PROJECT_ROOT/display_controller.py"
+    echo "$WEB_USER ALL=(ALL) NOPASSWD: $BASH_PATH $PROJECT_ROOT/start_display.sh"
+    echo "$WEB_USER ALL=(ALL) NOPASSWD: $BASH_PATH $PROJECT_ROOT/stop_display.sh"
     echo ""
     echo "# Allow web user to remove plugin directories via vetted helper script"
     echo "# The helper validates that the target path resolves inside plugin-repos/ or plugins/"
     echo "$WEB_USER ALL=(ALL) NOPASSWD: $BASH_PATH $SAFE_RM_PATH *"
+    echo ""
+    echo "# Allow web user to install a plugin's requirements.txt as root via vetted"
+    echo "# helper script, so packages are visible to root-run ledmatrix.service"
+    echo "# (not just the web interface's own user). The helper validates the target"
+    echo "# is requirements.txt at the project root or under plugin-repos/ or plugins/."
+    echo "$WEB_USER ALL=(ALL) NOPASSWD: $BASH_PATH $SAFE_PIP_INSTALL_PATH *"
 } > "$TEMP_SUDOERS"
 
 echo ""
@@ -126,6 +141,7 @@ echo "- Run display_controller.py directly"
 echo "- Execute start_display.sh and stop_display.sh"
 echo "- Reboot and shutdown the system"
 echo "- Remove plugin directories (for update/uninstall when root-owned files block deletion)"
+echo "- Install plugin/base requirements.txt as root (so ledmatrix.service can see them)"
 echo ""
 
 # Ask for confirmation
@@ -147,6 +163,13 @@ fi
 if ! sudo chmod 755 "$SAFE_RM_PATH"; then
     echo "Warning: Could not set permissions on $SAFE_RM_PATH"
 fi
+echo "Hardening safe_pip_install.sh ownership..."
+if ! sudo chown root:root "$SAFE_PIP_INSTALL_PATH"; then
+    echo "Warning: Could not set ownership on $SAFE_PIP_INSTALL_PATH"
+fi
+if ! sudo chmod 755 "$SAFE_PIP_INSTALL_PATH"; then
+    echo "Warning: Could not set permissions on $SAFE_PIP_INSTALL_PATH"
+fi
 
 if sudo cp "$TEMP_SUDOERS" /etc/sudoers.d/ledmatrix_web; then
     echo "Configuration applied successfully!"
@@ -160,7 +183,7 @@ if sudo cp "$TEMP_SUDOERS" /etc/sudoers.d/ledmatrix_web; then
         echo "✗ systemctl status ledmatrix.service - Failed"
     fi
     
-    if sudo -n test -f "$PROJECT_DIR/start_display.sh"; then
+    if sudo -n test -f "$PROJECT_ROOT/start_display.sh"; then
         echo "✓ File access test - OK"
     else
         echo "✗ File access test - Failed"

scripts/render_plugin.py

@@ -28,7 +28,7 @@ os.environ['EMULATOR'] = 'true'
 # Import logger after path setup so src.logging_config is importable
 from src.logging_config import get_logger  # noqa: E402
 from src.plugin_system.testing.loading import (  # noqa: E402
-    find_plugin_dir, load_manifest, load_config_defaults,
+    build_full_config, find_plugin_dir, load_manifest,
 )
 logger = get_logger("[Render Plugin]")
 
@@ -83,16 +83,13 @@ def main() -> int:
     manifest = load_manifest(Path(plugin_dir))
 
     # Parse config: start with schema defaults, then apply overrides
-    config_defaults = load_config_defaults(Path(plugin_dir))
     try:
         user_config = json.loads(args.config)
     except json.JSONDecodeError as e:
         logger.error("Invalid JSON config: %s", e)
         return 1
 
-    config = {'enabled': True}
-    config.update(config_defaults)
-    config.update(user_config)
+    config = build_full_config(Path(plugin_dir), cli_config=user_config)
 
     # Load mock data if provided
     mock_data = {}

scripts/templates/dev_preview.html

@@ -209,6 +209,11 @@
                            onchange="onConfigChange()">
                     <span class="text-xs ml-2" style="color: var(--text-secondary);">px</span>
                 </div>
+                <select id="sizePreset" onchange="applySizePreset()"
+                        class="w-full mt-2 px-2 py-1.5 rounded text-xs"
+                        style="background: var(--bg-primary); color: var(--text-secondary); border: 1px solid var(--border-color);">
+                    <option value="">Preset sizes…</option>
+                </select>
             </div>
 
             <!-- Config form -->
@@ -242,13 +247,18 @@
                 </div>
             </details>
 
-            <!-- Render button -->
+            <!-- Render buttons -->
             <div class="flex gap-2">
                 <button onclick="renderPlugin()" id="renderBtn"
                         class="flex-1 px-4 py-2.5 rounded-lg text-sm font-medium text-white"
                         style="background: var(--accent);">
                     Render
                 </button>
+                <button onclick="renderAllSizes()" id="renderAllBtn" title="Render at every harness test size"
+                        class="px-4 py-2.5 rounded-lg text-sm font-medium"
+                        style="background: var(--bg-tertiary); color: var(--text-primary); border: 1px solid var(--border-color);">
+                    All Sizes
+                </button>
             </div>
         </div>
 
@@ -311,6 +321,15 @@
             <div id="messagesPanel" class="panel p-3 hidden">
                 <div id="messagesList" class="text-xs font-mono space-y-1"></div>
             </div>
+
+            <!-- Multi-size gallery -->
+            <div id="galleryPanel" class="panel p-4 hidden">
+                <div class="flex items-center justify-between mb-3">
+                    <span class="text-xs font-medium" style="color: var(--text-secondary);">All Sizes</span>
+                    <span class="text-xs" style="color: var(--text-secondary);" id="galleryStatus"></span>
+                </div>
+                <div id="galleryGrid" class="flex flex-wrap gap-4 items-start"></div>
+            </div>
         </div>
     </div>
 
@@ -340,8 +359,30 @@
                 opt.textContent = `${p.name} (${p.id})`;
                 select.appendChild(opt);
             });
+
+            // Load harness size presets
+            try {
+                const sizesRes = await fetch('/api/sizes');
+                const sizesData = await sizesRes.json();
+                const preset = document.getElementById('sizePreset');
+                (sizesData.sizes || []).forEach(([w, h]) => {
+                    const opt = document.createElement('option');
+                    opt.value = `${w}x${h}`;
+                    opt.textContent = `${w} x ${h}`;
+                    preset.appendChild(opt);
+                });
+            } catch (e) { /* presets are a convenience; ignore */ }
         });
 
+        function applySizePreset() {
+            const value = document.getElementById('sizePreset').value;
+            if (!value) return;
+            const [w, h] = value.split('x');
+            document.getElementById('displayWidth').value = w;
+            document.getElementById('displayHeight').value = h;
+            onConfigChange();
+        }
+
         // ---------- Plugin selection ----------
         async function onPluginChange() {
             const pluginId = document.getElementById('pluginSelect').value;
@@ -485,6 +526,89 @@
             }
         }
 
+        // ---------- Multi-size gallery ----------
+        async function renderAllSizes() {
+            if (!currentPluginId) return;
+
+            const btn = document.getElementById('renderAllBtn');
+            const panel = document.getElementById('galleryPanel');
+            const grid = document.getElementById('galleryGrid');
+            const status = document.getElementById('galleryStatus');
+            btn.disabled = true;
+            btn.textContent = 'Rendering…';
+            panel.classList.remove('hidden');
+            grid.innerHTML = '';
+            status.textContent = 'Rendering at all harness sizes…';
+
+            const config = jsonEditor ? jsonEditor.getValue() : {};
+            config.enabled = true;
+            let mockData = {};
+            const mockInput = document.getElementById('mockDataInput').value.trim();
+            if (mockInput) {
+                try { mockData = JSON.parse(mockInput); }
+                catch (e) { showMessages([], [`Mock data JSON error: ${e.message}`]); }
+            }
+
+            try {
+                const res = await fetch('/api/render-matrix', {
+                    method: 'POST',
+                    headers: { 'Content-Type': 'application/json' },
+                    body: JSON.stringify({
+                        plugin_id: currentPluginId,
+                        config: config,
+                        mock_data: mockData,
+                    }),
+                });
+                const data = await res.json();
+                if (data.error) {
+                    status.textContent = data.error;
+                    return;
+                }
+
+                let failures = 0;
+                (data.results || []).forEach(r => {
+                    const cell = document.createElement('div');
+                    cell.style.cssText = 'display:flex;flex-direction:column;gap:4px;';
+                    const failed = (r.errors || []).length > 0 || !r.image;
+                    if (failed) failures++;
+
+                    const label = document.createElement('span');
+                    label.className = 'text-xs font-mono';
+                    label.style.color = failed ? '#f87171' : 'var(--text-secondary)';
+                    label.textContent = `${r.width}x${r.height} · ${r.render_time_ms}ms`;
+                    cell.appendChild(label);
+
+                    if (r.image) {
+                        const img = document.createElement('img');
+                        img.src = r.image;
+                        // Small panels get 2x zoom so they stay legible in the grid
+                        const zoom = r.height >= 128 ? 1 : 2;
+                        img.style.cssText =
+                            `image-rendering: pixelated; width:${r.width * zoom}px; ` +
+                            `height:${r.height * zoom}px; ` +
+                            `border:1px solid ${failed ? '#f87171' : 'var(--border-color)'};`;
+                        cell.appendChild(img);
+                    }
+                    if (failed) {
+                        const err = document.createElement('span');
+                        err.className = 'text-xs font-mono';
+                        err.style.color = '#f87171';
+                        err.textContent = (r.errors || ['render failed']).join('; ');
+                        cell.appendChild(err);
+                    }
+                    grid.appendChild(cell);
+                });
+                status.textContent = failures
+                    ? `${failures} size(s) failed`
+                    : `${(data.results || []).length} sizes rendered`;
+            } catch (e) {
+                status.textContent = `Network error: ${e.message}`;
+            } finally {
+                btn.disabled = false;
+                btn.textContent = 'All Sizes';
+            }
+        }
+
         // ---------- Zoom ----------
         function updateZoom() {
             const zoom = parseInt(document.getElementById('zoomSlider').value);

scripts/utils/wifi_monitor_daemon.py

@@ -78,21 +78,17 @@ class WiFiMonitorDaemon:
         
         while self.running:
             try:
-                # Get current status before checking
-                status = self.wifi_manager.get_wifi_status()
-                ethernet_connected = self.wifi_manager._is_ethernet_connected()
-                
-                # Check WiFi status and manage AP mode
-                state_changed = self.wifi_manager.check_and_manage_ap_mode()
-                
-                # Get updated status after check
-                updated_status = self.wifi_manager.get_wifi_status()
-                updated_ethernet = self.wifi_manager._is_ethernet_connected()
-                
+                # One combined check that also returns the state it observed —
+                # the previous flow fetched status before AND after the check
+                # on top of the check's own internal fetch, each one several
+                # nmcli subprocess forks, every 30s, forever.
+                (state_changed, updated_status, updated_ethernet,
+                 ap_active) = self.wifi_manager.check_and_manage_ap_mode_with_state()
+
                 current_state = {
                     'connected': updated_status.connected,
                     'ethernet_connected': updated_ethernet,
-                    'ap_active': updated_status.ap_mode_active,
+                    'ap_active': ap_active,
                     'ssid': updated_status.ssid
                 }
                 
@@ -109,7 +105,7 @@ class WiFiMonitorDaemon:
                     else:
                         logger.debug("Ethernet not connected")
                     
-                    if updated_status.ap_mode_active:
+                    if ap_active:
                         logger.info(f"AP mode ACTIVE - SSID: {ap_ssid} (IP: 192.168.4.1)")
                     else:
                         logger.debug("AP mode inactive")
@@ -123,16 +119,16 @@ class WiFiMonitorDaemon:
                     # Log periodic status (less verbose)
                     if updated_status.connected:
                         logger.debug(f"Status check: WiFi={updated_status.ssid} ({updated_status.signal}%), "
-                                   f"Ethernet={updated_ethernet}, AP={updated_status.ap_mode_active}")
+                                   f"Ethernet={updated_ethernet}, AP={ap_active}")
                     else:
-                        logger.debug(f"Status check: WiFi=disconnected, Ethernet={updated_ethernet}, AP={updated_status.ap_mode_active}")
+                        logger.debug(f"Status check: WiFi=disconnected, Ethernet={updated_ethernet}, AP={ap_active}")
                 
                 # Escalating recovery: if nmcli reports connected but actual internet
                 # is unreachable for several consecutive checks, restart NetworkManager.
                 # This is done HERE (not inside check_and_manage_ap_mode) to keep the
                 # AP-enable trigger clean and avoid false-positive AP enables from
                 # transient packet loss on otherwise working WiFi.
-                if updated_status.connected and not updated_status.ap_mode_active:
+                if updated_status.connected and not ap_active:
                     if not self.wifi_manager.check_internet_connectivity():
                         self._consecutive_internet_failures += 1
                         logger.warning(

src/__init__.py

@@ -4,5 +4,5 @@ LEDMatrix Display System
 Core source package for the LED Matrix Display project.
 """
 
-__version__ = "1.0.0"
+__version__ = "3.1.0"
 

src/adaptive_images.py

@@ -0,0 +1,174 @@
+"""
+Adaptive image fitting for plugins — the image counterpart to
+src/adaptive_layout.py's text fitting.
+
+Promotes the proven in-field image patterns into one shared helper so
+plugins stop hand-copying resize/cache code:
+
+- "crop transparent padding, then fill the row height" (football/hockey
+  logo pattern) -> ``crop_to_ink=True, mode="fill_height"``
+- "crop-to-fill with a top anchor for faces" (masters-tournament headshot
+  pattern) -> ``mode="cover", anchor="top"``
+- "letterbox to fit, centered on a background" (static-image pattern)
+  -> ``mode="contain"``
+- NEAREST for pixel art/flags vs LANCZOS for photos (masters flag pattern)
+  -> ``resample=RESAMPLE_NEAREST``
+
+Unlike PIL's ``thumbnail()`` (downscale-only — the reason plugin imagery
+stays tiny on big panels), ``fit_image`` upscales by default so content
+genuinely adapts to larger displays; pass ``upscale=False`` for the old
+behavior.
+
+Use via ``LayoutContext.fit_image(...)`` (cached per panel size) or
+``BasePlugin.draw_image(...)``; the module-level functions are the
+uncached primitives.
+"""
+
+from dataclasses import dataclass
+from typing import Any, Optional, Tuple
+
+from PIL import Image
+
+# The one Pillow >= 9.1 compat shim (replaces the per-plugin copies).
+try:
+    RESAMPLE_LANCZOS = Image.Resampling.LANCZOS
+    RESAMPLE_NEAREST = Image.Resampling.NEAREST
+except AttributeError:  # Pillow < 9.1
+    RESAMPLE_LANCZOS = Image.LANCZOS
+    RESAMPLE_NEAREST = Image.NEAREST
+
+FIT_MODES = ("contain", "cover", "fill_height", "stretch")
+
+
+@dataclass(frozen=True)
+class ImageFitResult:
+    """A processed RGBA copy of a source image, sized for a target box."""
+    image: Image.Image
+    width: int
+    height: int
+    scale: float          # scale applied vs the (possibly ink-cropped) source
+    mode: str
+    source_size: Tuple[int, int]
+
+    @property
+    def is_empty(self) -> bool:
+        return self.width <= 0 or self.height <= 0
+
+
+_EMPTY_IMAGE = Image.new("RGBA", (1, 1), (0, 0, 0, 0))
+
+
+def _empty_result(mode: str, source_size: Tuple[int, int]) -> ImageFitResult:
+    return ImageFitResult(_EMPTY_IMAGE, 0, 0, 0.0, mode, source_size)
+
+
+def _box_dims(box: Any) -> Tuple[int, int]:
+    """Accept a Region (duck-typed .w/.h) or a (w, h) tuple."""
+    if hasattr(box, "w") and hasattr(box, "h"):
+        return (int(box.w), int(box.h))
+    w, h = box
+    return (int(w), int(h))
+
+
+def fit_image(img: Image.Image, box: Any, *, mode: str = "contain",
+              crop_to_ink: bool = False, anchor: str = "center",
+              resample: Any = None, upscale: bool = True) -> ImageFitResult:
+    """Fit an image into a box, preserving crispness policy per content type.
+
+    Args:
+        img: Source PIL image (any mode; output is always RGBA).
+        box: Region or (w, h) target box.
+        mode: "contain" (letterbox), "cover" (crop-to-fill),
+              "fill_height" (height == box height, contain-capped by width),
+              "stretch" (exact resize).
+        crop_to_ink: Trim fully-transparent padding (getbbox) before fitting —
+              logos shipped with generous padding otherwise render small.
+        anchor: For "cover" crops: "center" or "top" (keeps faces/tops).
+        resample: PIL resampling filter; defaults to RESAMPLE_LANCZOS.
+              Use RESAMPLE_NEAREST for pixel art, flags, and sprite icons.
+        upscale: Allow scaling above source size (default True — the adaptive
+              point). False mimics the legacy thumbnail() behavior.
+    """
+    if mode not in FIT_MODES:
+        raise ValueError(f"Unknown fit mode '{mode}' (expected one of {FIT_MODES})")
+    box_w, box_h = _box_dims(box)
+    if box_w <= 0 or box_h <= 0 or img.width <= 0 or img.height <= 0:
+        return _empty_result(mode, img.size)
+
+    resample = RESAMPLE_LANCZOS if resample is None else resample
+
+    work = img if img.mode == "RGBA" else img.convert("RGBA")
+    if crop_to_ink:
+        bbox = work.getbbox()
+        if bbox is None:  # fully transparent
+            return _empty_result(mode, img.size)
+        work = work.crop(bbox)
+
+    src_w, src_h = work.size
+
+    if mode == "stretch":
+        out = work.resize((box_w, box_h), resample)
+        return ImageFitResult(out, box_w, box_h, box_w / src_w, mode, (src_w, src_h))
+
+    if mode == "cover":
+        scale = max(box_w / src_w, box_h / src_h)
+        if not upscale:
+            scale = min(scale, 1.0)
+        scaled_w = max(1, round(src_w * scale))
+        scaled_h = max(1, round(src_h * scale))
+        out = work.resize((scaled_w, scaled_h), resample)
+        # Crop the overhang down to the box (only when the scaled image is
+        # larger; with upscale=False it may be smaller and is left as-is).
+        crop_w, crop_h = min(box_w, scaled_w), min(box_h, scaled_h)
+        left = (scaled_w - crop_w) // 2
+        top = 0 if anchor == "top" else (scaled_h - crop_h) // 2
+        out = out.crop((left, top, left + crop_w, top + crop_h))
+        return ImageFitResult(out, out.width, out.height, scale, mode, (src_w, src_h))
+
+    # contain / fill_height share the "preserve aspect, no crop" path
+    if mode == "fill_height":
+        scale = box_h / src_h
+        # contain-cap: never exceed the box width (football's logo_slot rule)
+        scale = min(scale, box_w / src_w)
+    else:  # contain
+        scale = min(box_w / src_w, box_h / src_h)
+    if not upscale:
+        scale = min(scale, 1.0)
+    out_w = max(1, round(src_w * scale))
+    out_h = max(1, round(src_h * scale))
+    if (out_w, out_h) == (src_w, src_h):
+        # No resize needed — but `work` may still BE the caller's original
+        # image (RGBA source, no ink crop). The result must always be an
+        # independent copy: LayoutContext caches ImageFitResults, and an
+        # aliased image would let later mutations of the source corrupt
+        # cached fits (or vice versa).
+        out = work.copy() if work is img else work
+    else:
+        out = work.resize((out_w, out_h), resample)
+    return ImageFitResult(out, out_w, out_h, scale, mode, (src_w, src_h))
+
+
+def draw_fitted_image(display_manager: Any, ifit: ImageFitResult, box: Any, *,
+                      align: str = "center", valign: str = "center",
+                      offset: Tuple[int, int] = (0, 0)) -> Optional[Tuple[int, int]]:
+    """Paste a fitted image aligned within a Region onto the display canvas.
+
+    Pastes with the image's own alpha mask. Returns the (x, y) actually used
+    so callers can position adjacent decorations, or None when nothing was
+    drawn (empty fit / no canvas).
+    """
+    if ifit is None or ifit.is_empty:
+        return None
+    image = getattr(display_manager, "image", None)
+    if image is None:
+        return None
+    if hasattr(box, "align_xy"):
+        x, y = box.align_xy(ifit.width, ifit.height, align, valign)
+    else:
+        box_w, box_h = _box_dims(box)
+        x = (box_w - ifit.width) // 2
+        y = (box_h - ifit.height) // 2
+    x += int(offset[0])
+    y += int(offset[1])
+    image.paste(ifit.image, (x, y), ifit.image)
+    return (x, y)

src/adaptive_layout.py

@@ -0,0 +1,746 @@
+"""
+Adaptive layout and font scaling helpers for plugins.
+
+Generalizes the three size-adaptation patterns proven in the plugin
+ecosystem into small composable core helpers, so plugins render legibly on
+any panel size (64x32, 128x32, 96x48, 128x64, 256x64, ...) without
+hand-tuned per-display layouts:
+
+- Region: integer rect algebra (bands, columns, weighted splits, centering).
+  Regions partition space, so text bands can't overlap by construction —
+  replacing the magic ``y = 1`` / ``y = height - 7`` offsets tuned for 128x32.
+- Font ladders: ordered (family, size) steps known to render crisply.
+  Pixel fonts (BDF, PressStart2P) only look right at native/integer sizes,
+  so fonts are never scaled continuously — fitting walks a ladder from the
+  largest rung down until the measured text fits the target box. This is
+  baseball-scoreboard's fallback-ladder pattern promoted to core.
+- LayoutContext: per-(width, height) facts — breakpoint tiers
+  (masters-tournament's pattern), a geometry scale factor vs. a declared
+  design size (f1-scoreboard's pattern), and cached fit-text queries.
+
+Everything is opt-in: plugins get a context via ``self.layout`` on
+BasePlugin (or construct one directly) and existing plugins are unaffected.
+
+Fonts are resolved through FontManager's catalog (family names are
+lowercased file stems from assets/fonts, e.g. "9x15", "tom-thumb", plus
+aliases like "press_start"). FitResult.font is a plain PIL font or
+freetype.Face, so it drops straight into DisplayManager.draw_text().
+"""
+
+import logging
+from collections import OrderedDict
+from dataclasses import dataclass
+from typing import Any, Dict, List, Optional, Sequence, Tuple, Union
+
+import freetype
+
+logger = logging.getLogger(__name__)
+
+# Height-based breakpoint tiers, smallest to largest. A 32px-tall panel is
+# the ecosystem baseline ("sm"); 96x48 lands in "md"; 128x64 in "lg".
+_HEIGHT_TIERS: Tuple[Tuple[str, int], ...] = (
+    ("xs", 16), ("sm", 32), ("md", 48), ("lg", 64), ("xl", 10 ** 9),
+)
+TIER_ORDER: Tuple[str, ...] = tuple(name for name, _ in _HEIGHT_TIERS)
+
+_WIDTH_TIERS: Tuple[Tuple[str, int], ...] = (
+    ("narrow", 64), ("normal", 128), ("wide", 256), ("ultrawide", 10 ** 9),
+)
+WIDTH_TIER_ORDER: Tuple[str, ...] = tuple(name for name, _ in _WIDTH_TIERS)
+
+# The panel size most existing plugins were authored against.
+DEFAULT_DESIGN_SIZE: Tuple[int, int] = (128, 32)
+
+
+@dataclass(frozen=True)
+class Region:
+    """An integer rectangle. Carving methods return sub-Regions clamped to
+    non-negative dimensions, so degenerate panels never produce negative
+    boxes — a band request larger than the region simply consumes it all."""
+
+    x: int
+    y: int
+    w: int
+    h: int
+
+    def __post_init__(self):
+        object.__setattr__(self, "w", max(0, int(self.w)))
+        object.__setattr__(self, "h", max(0, int(self.h)))
+        object.__setattr__(self, "x", int(self.x))
+        object.__setattr__(self, "y", int(self.y))
+
+    @property
+    def right(self) -> int:
+        return self.x + self.w
+
+    @property
+    def bottom(self) -> int:
+        return self.y + self.h
+
+    @property
+    def center(self) -> Tuple[int, int]:
+        return (self.x + self.w // 2, self.y + self.h // 2)
+
+    # ---- carving -----------------------------------------------------
+
+    def inset(self, dx: int, dy: Optional[int] = None) -> "Region":
+        """Shrink by dx horizontally and dy (default dx) vertically, each side."""
+        if dy is None:
+            dy = dx
+        return Region(self.x + dx, self.y + dy, self.w - 2 * dx, self.h - 2 * dy)
+
+    def offset(self, dx: int, dy: int) -> "Region":
+        """Translate without resizing — the hook for user x/y-offset
+        customization: compute regions first, then apply the user's
+        configured offsets as a final translation."""
+        return Region(self.x + dx, self.y + dy, self.w, self.h)
+
+    def top_band(self, h: int) -> "Region":
+        return Region(self.x, self.y, self.w, min(h, self.h))
+
+    def bottom_band(self, h: int) -> "Region":
+        h = min(h, self.h)
+        return Region(self.x, self.bottom - h, self.w, h)
+
+    def middle(self, top_h: int = 0, bottom_h: int = 0) -> "Region":
+        """What remains between a top band and a bottom band."""
+        return Region(self.x, self.y + top_h, self.w, self.h - top_h - bottom_h)
+
+    def left_col(self, w: int) -> "Region":
+        return Region(self.x, self.y, min(w, self.w), self.h)
+
+    def right_col(self, w: int) -> "Region":
+        w = min(w, self.w)
+        return Region(self.right - w, self.y, w, self.h)
+
+    def split_h(self, *weights: float, gap: int = 0) -> List["Region"]:
+        """Side-by-side columns sized by weight; gaps between them."""
+        sizes = _weighted_sizes(self.w, weights, gap)
+        cols, cursor = [], self.x
+        for size in sizes:
+            cols.append(Region(cursor, self.y, size, self.h))
+            cursor += size + gap
+        return cols
+
+    def split_v(self, *weights: float, gap: int = 0) -> List["Region"]:
+        """Stacked rows sized by weight; gaps between them."""
+        sizes = _weighted_sizes(self.h, weights, gap)
+        rows, cursor = [], self.y
+        for size in sizes:
+            rows.append(Region(self.x, cursor, self.w, size))
+            cursor += size + gap
+        return rows
+
+    # ---- placement ---------------------------------------------------
+
+    def align_xy(self, w: int, h: int, align: str = "center",
+                 valign: str = "center") -> Tuple[int, int]:
+        """Top-left position for a w x h box aligned within this region.
+        align: left|center|right; valign: top|center|bottom."""
+        if align == "left":
+            x = self.x
+        elif align == "right":
+            x = self.right - w
+        else:
+            x = self.x + (self.w - w) // 2
+        if valign == "top":
+            y = self.y
+        elif valign == "bottom":
+            y = self.bottom - h
+        else:
+            y = self.y + (self.h - h) // 2
+        return (x, y)
+
+    def center_xy(self, w: int, h: int) -> Tuple[int, int]:
+        return self.align_xy(w, h)
+
+    def contains(self, w: int, h: int) -> bool:
+        return w <= self.w and h <= self.h
+
+
+def _weighted_sizes(total: int, weights: Sequence[float], gap: int) -> List[int]:
+    """Integer sizes proportional to weights, remainder spread left-to-right."""
+    if not weights:
+        return []
+    usable = max(0, total - gap * (len(weights) - 1))
+    weight_sum = sum(weights) or 1
+    sizes = [int(usable * w / weight_sum) for w in weights]
+    remainder = usable - sum(sizes)
+    for i in range(remainder):
+        sizes[i % len(sizes)] += 1
+    return sizes
+
+
+# ---------------------------------------------------------------------------
+# Font ladders
+# ---------------------------------------------------------------------------
+
+@dataclass(frozen=True)
+class FontStep:
+    """One rung: a FontManager catalog family at a size it renders crisply."""
+    family: str
+    size_px: int
+
+
+FontLadder = Tuple[FontStep, ...]
+
+# X11 BDF bitmap fonts at their native pixel sizes, largest to smallest —
+# baseball-scoreboard's fallback ladder extended upward. Same-height rungs
+# are ordered widest first so width-constrained text steps to a narrower
+# face before dropping a size.
+LADDER_GRID: FontLadder = (
+    FontStep("10x20", 20),
+    FontStep("9x18", 18),
+    FontStep("9x15", 15),
+    FontStep("8x13", 13),
+    FontStep("7x13", 13),
+    FontStep("6x13", 13),
+    FontStep("6x12", 12),
+    FontStep("6x10", 10),
+    FontStep("6x9", 9),
+    FontStep("5x8", 8),
+    FontStep("5x7", 7),
+    FontStep("4x6", 6),
+    FontStep("tom-thumb", 6),
+)
+
+# PressStart2P at integer multiples of its 8px pixel grid only — fractional
+# sizes blur a pixel font. For headline text (clocks, scores).
+LADDER_ARCADE: FontLadder = (
+    FontStep("press_start", 32),
+    FontStep("press_start", 24),
+    FontStep("press_start", 16),
+    FontStep("press_start", 8),
+)
+
+LADDER_DEFAULT: FontLadder = LADDER_GRID
+
+ELLIPSIS = "…"
+
+
+@dataclass(frozen=True)
+class FitResult:
+    """A fitted font plus the ink metrics of the (possibly ellipsized) text.
+
+    ``y_offset`` is the gap between the y passed to draw_text() and where
+    ink actually starts; subtract it from the desired ink-top position when
+    drawing (draw_fitted_text does this for you).
+    """
+    font: Any
+    family: str
+    size_px: int
+    text: str
+    width: int
+    height: int
+    baseline: int
+    y_offset: int
+    fits: bool
+    line_height: int = 0
+
+
+def measure_ink(text: str, font: Any) -> Tuple[int, int, int, int]:
+    """Measure the ink box of text: (width, height, baseline, y_offset).
+
+    y_offset is the distance from the y coordinate DisplayManager.draw_text()
+    is given to the top of the actual ink — PIL draws TTF from the em-box
+    top and _draw_bdf_text derives the baseline from y + ascender, so both
+    leave a font-dependent gap that matters when centering in short bands.
+    """
+    if isinstance(font, freetype.Face):
+        width = 0
+        ascender = font.size.ascender >> 6
+        ink_top, ink_bottom = None, None
+        for char in text:
+            font.load_char(char)
+            width += font.glyph.advance.x >> 6
+            rows = font.glyph.bitmap.rows
+            if rows:
+                top = ascender - font.glyph.bitmap_top
+                ink_top = top if ink_top is None else min(ink_top, top)
+                ink_bottom = top + rows if ink_bottom is None else max(ink_bottom, top + rows)
+        if ink_top is None:
+            ink_top, ink_bottom = 0, 0
+        return (width, ink_bottom - ink_top, ascender, ink_top)
+    bbox = font.getbbox(text)
+    return (bbox[2] - bbox[0], bbox[3] - bbox[1], -bbox[1], bbox[1])
+
+
+def font_line_height(font: Any) -> int:
+    """Recommended line spacing for a font (matches DisplayManager.get_font_height)."""
+    if isinstance(font, freetype.Face):
+        return font.size.height >> 6
+    ascent, descent = font.getmetrics()
+    return ascent + descent
+
+
+def measure_font_crispness(font: Any, sample_text: str = "Ay0",
+                           canvas_size: Tuple[int, int] = (250, 60)) -> float:
+    """Fraction of the rendered sample's ink-bbox pixels that are neither
+    pure black nor pure white — i.e. antialiased.
+
+    BDF (freetype.Face) glyphs are true bitmaps and always render at 0.0.
+    "Pixel-style" TTFs (PressStart2P, and similar fonts bundled for
+    plugins that draw through ImageDraw.text() and so can't take a BDF
+    face) are NOT automatically crisp at arbitrary sizes — PIL antialiases
+    TTF outlines by default, and a pixel-grid font only lands on whole
+    pixels at specific sizes (for PressStart2P: exact multiples of 8).
+    Requesting an unverified size silently produces soft/blurry glyphs on
+    an LED panel, which reads as fuzzy compared to a true BDF rung.
+
+    Use this to vet any custom FontLadder rung that mixes TTF fonts before
+    shipping it — see test_adaptive_layout.py::test_ladder_is_crisp for the
+    pattern. A rung should score 0.0 (or very close, to allow for the odd
+    diagonal stroke) before it belongs in a "crisp" ladder.
+    """
+    if isinstance(font, freetype.Face):
+        return 0.0
+    from PIL import Image, ImageDraw
+    img = Image.new("L", canvas_size, 0)
+    ImageDraw.Draw(img).text((2, 2), sample_text, font=font, fill=255)
+    bbox = img.getbbox()
+    if bbox is None:
+        return 0.0
+    pixels = img.crop(bbox).tobytes()
+    pure = sum(1 for p in pixels if p == 0 or p == 255)
+    return (len(pixels) - pure) / len(pixels)
+
+
+class LayoutContext:
+    """Per-render-size layout facts and fit-text queries for one panel size.
+
+    Construct once per (width, height); BasePlugin.layout does this and
+    rebuilds automatically when the logical display size changes.
+    """
+
+    def __init__(self, width: int, height: int, font_manager: Any,
+                 design_size: Tuple[int, int] = DEFAULT_DESIGN_SIZE):
+        self.width = int(width)
+        self.height = int(height)
+        self.font_manager = font_manager
+        self.design_size = design_size
+        self.bounds = Region(0, 0, self.width, self.height)
+        self.aspect = self.width / max(1, self.height)
+        self.tier = _pick_tier(_HEIGHT_TIERS, self.height)
+        self.width_tier = _pick_tier(_WIDTH_TIERS, self.width)
+        self.is_wide_short = self.aspect >= 2.5 and self.height <= 32
+        design_w, design_h = design_size
+        # Geometry scale only (gaps, icon/logo sizes) — never applied to
+        # fonts, which step between crisp ladder rungs instead.
+        self.scale = min(self.width / max(1, design_w),
+                         self.height / max(1, design_h))
+        # LRU-bounded: entries are small, but keys embed the fitted TEXT —
+        # a plugin fitting changing text (a live game clock, a ticker) on a
+        # 24/7 service would otherwise grow this without bound.
+        self._fit_cache: "OrderedDict[Any, FitResult]" = OrderedDict()
+        # LRU-bounded (images are big). Entries hold a strong reference to
+        # the source image when keyed by id() so the id can't be recycled
+        # out from under the cache.
+        self._image_cache: "OrderedDict[Any, Tuple[Any, Any]]" = OrderedDict()
+
+    _IMAGE_CACHE_MAX = 64
+    _FIT_CACHE_MAX = 512
+
+    def _fit_cache_get(self, key: Any) -> Optional["FitResult"]:
+        cached = self._fit_cache.get(key)
+        if cached is not None:
+            self._fit_cache.move_to_end(key)
+        return cached
+
+    def _fit_cache_put(self, key: Any, result: "FitResult") -> None:
+        self._fit_cache[key] = result
+        while len(self._fit_cache) > self._FIT_CACHE_MAX:
+            self._fit_cache.popitem(last=False)
+
+    # ---- the three adaptation patterns --------------------------------
+
+    def px(self, base: int, minimum: int = 1, maximum: Optional[int] = None) -> int:
+        """Scale a design-size pixel measurement (f1's pattern): gaps,
+        icon sizes, logo slots. Clamped to [minimum, maximum]."""
+        value = max(minimum, round(base * self.scale))
+        if maximum is not None:
+            value = min(value, maximum)
+        return value
+
+    def by_tier(self, mapping: Dict[str, Any], default: Any = None) -> Any:
+        """Pick the value for the nearest defined tier at-or-below the
+        panel's height tier (masters' pattern). Falls forward to the
+        smallest defined tier above, then to default.
+
+        by_tier({"sm": 10, "lg": 18}) -> 10 on 128x32, 18 on 128x64.
+        Keys may also use width tiers ("narrow", "wide", ...)."""
+        order = TIER_ORDER if any(k in TIER_ORDER for k in mapping) else WIDTH_TIER_ORDER
+        current = self.tier if order is TIER_ORDER else self.width_tier
+        idx = order.index(current)
+        for name in reversed(order[: idx + 1]):
+            if name in mapping:
+                return mapping[name]
+        for name in order[idx + 1:]:
+            if name in mapping:
+                return mapping[name]
+        return default
+
+    def fit_text(self, text: str, box: Union[Region, Tuple[int, int]],
+                 ladder: FontLadder = LADDER_DEFAULT,
+                 ellipsis: bool = True) -> FitResult:
+        """Largest ladder rung whose rendered text fits the box (baseball's
+        pattern). If even the smallest rung is too wide, the text is
+        ellipsized to fit (unless ellipsis=False); fits=False only when no
+        acceptable rendering exists."""
+        box_w, box_h = _box_dims(box)
+        key = ("text", text, box_w, box_h, ladder, ellipsis)
+        cached = self._fit_cache_get(key)
+        if cached is not None:
+            return cached
+        result = self._walk_ladder(text, ladder, box_w, box_h, ellipsis)
+        self._fit_cache_put(key, result)
+        return result
+
+    def fit_text_proportional(self, text: str, box: Union[Region, Tuple[int, int]],
+                              base_size_px: int, ladder: FontLadder = LADDER_DEFAULT,
+                              ellipsis: bool = True,
+                              scale: Optional[float] = None) -> FitResult:
+        """Ladder rung closest to (but not exceeding) ``base_size_px * scale``
+        that still fits the box — proportional sizing instead of ``fit_text``'s
+        "always maximize" behavior.
+
+        Use this when several independently-fitted elements need to stay
+        visually harmonious as the panel grows (e.g. a scoreboard's score,
+        status, and detail text) — ``fit_text`` maximizes each one within
+        its own region, which can make one element balloon out of
+        proportion to its neighbors (a huge score overlapping logos it fit
+        fine at the design size) even though every individual pick is
+        independently "correct". ``base_size_px`` is the size that element
+        renders at on the design size (``design_size``, typically 128x32)
+        — commonly a plugin's existing classic/fixed font size for that
+        element.
+
+        ``scale`` defaults to ``self.scale`` (the same conservative
+        min(width_ratio, height_ratio) factor ``px()`` uses — safe for
+        content whose aspect ratio matters). Pass an explicit axis-specific
+        value when the surrounding composition already scales that way —
+        e.g. a scoreboard whose logos scale with height alone
+        (``logo_slot = min(height, width // 2)``) should size its score
+        text by ``height / design_height`` too, or its text will look
+        under-scaled next to bigger logos on a panel that only grew taller.
+
+        Falls back to the smallest rung when even that exceeds the target
+        (a tiny scale factor), and to fit_text's ordinary smaller-rung
+        fallback when the closest-to-target rung doesn't actually fit the
+        box.
+        """
+        box_w, box_h = _box_dims(box)
+        effective_scale = self.scale if scale is None else scale
+        key = ("text_prop", text, box_w, box_h, ladder, base_size_px, ellipsis, effective_scale)
+        cached = self._fit_cache_get(key)
+        if cached is not None:
+            return cached
+        target = base_size_px * effective_scale
+        eligible = [step for step in ladder if step.size_px <= target]
+        candidates = eligible if eligible else (min(ladder, key=lambda s: s.size_px),)
+        result = self._walk_ladder(text, candidates, box_w, box_h, ellipsis)
+        self._fit_cache_put(key, result)
+        return result
+
+    def _walk_ladder(self, text: str, ladder: Sequence[FontStep],
+                     box_w: int, box_h: int, ellipsis: bool) -> FitResult:
+        """Shared by fit_text/fit_text_proportional: first ladder entry (in
+        the order given) whose rendered text fits, ellipsizing the last one
+        tried if none do."""
+        result = None
+        for step in ladder:
+            font = self.font_manager.get_font(step.family, step.size_px)
+            width, height, baseline, y_offset = measure_ink(text, font)
+            result = FitResult(font, step.family, step.size_px, text,
+                               width, height, baseline, y_offset,
+                               fits=(width <= box_w and height <= box_h),
+                               line_height=font_line_height(font))
+            if result.fits:
+                break
+
+        if result is not None and not result.fits and ellipsis:
+            short = self.ellipsize(text, result.font, box_w)
+            width, height, baseline, y_offset = measure_ink(short, result.font)
+            result = FitResult(result.font, result.family, result.size_px,
+                               short, width, height, baseline, y_offset,
+                               fits=(width <= box_w and height <= box_h),
+                               line_height=result.line_height)
+        return result
+
+    def fit_lines(self, lines: Sequence[str], box: Union[Region, Tuple[int, int]],
+                  ladder: FontLadder = LADDER_DEFAULT,
+                  spacing: int = 1) -> FitResult:
+        """Largest rung where every line fits the box width and the stacked
+        lines (line_height + spacing apart) fit the box height. Measures the
+        actual strings, so a long line pushes the ladder down a rung a short
+        one wouldn't (baseball's multiline pattern). Text is the widest line."""
+        box_w, box_h = _box_dims(box)
+        key = ("lines", tuple(lines), box_w, box_h, ladder, spacing)
+        cached = self._fit_cache_get(key)
+        if cached is not None:
+            return cached
+
+        rows = max(1, len(lines))
+        result = None
+        for step in ladder:
+            font = self.font_manager.get_font(step.family, step.size_px)
+            line_h = font_line_height(font)
+            widest, metrics = "", (0, 0, 0, 0)
+            for line in lines:
+                m = measure_ink(line, font)
+                if m[0] >= metrics[0]:
+                    widest, metrics = line, m
+            total_h = rows * line_h + (rows - 1) * spacing
+            result = FitResult(font, step.family, step.size_px, widest,
+                               metrics[0], metrics[1], metrics[2], metrics[3],
+                               fits=(metrics[0] <= box_w and total_h <= box_h),
+                               line_height=line_h)
+            if result.fits:
+                break
+
+        self._fit_cache_put(key, result)
+        return result
+
+    def font_for_rows(self, rows: int, box_h: int,
+                      ladder: FontLadder = LADDER_GRID) -> FitResult:
+        """Largest rung whose line height lets `rows` rows fit in box_h
+        (baseball's traditional-scoreboard pattern). Measures a digit/cap
+        sample rather than specific strings."""
+        key = ("rows", rows, box_h, ladder)
+        cached = self._fit_cache_get(key)
+        if cached is not None:
+            return cached
+
+        sample = "0Ay"
+        result = None
+        for step in ladder:
+            font = self.font_manager.get_font(step.family, step.size_px)
+            line_h = font_line_height(font)
+            width, height, baseline, y_offset = measure_ink(sample, font)
+            result = FitResult(font, step.family, step.size_px, sample,
+                               width, height, baseline, y_offset,
+                               fits=(max(1, rows) * line_h <= box_h),
+                               line_height=line_h)
+            if result.fits:
+                break
+
+        self._fit_cache_put(key, result)
+        return result
+
+    # ---- images ---------------------------------------------------------
+
+    def fit_image(self, img: Any, box: Union[Region, Tuple[int, int]], *,
+                  mode: str = "contain", crop_to_ink: bool = False,
+                  anchor: str = "center", resample: Any = None,
+                  upscale: bool = True, cache_key: Any = None) -> Any:
+        """Fit an image into a box (see src/adaptive_images.py for modes),
+        cached per (image, box size, options) for this panel size.
+
+        Prefer a stable ``cache_key`` (e.g. "logo:KC") for images that get
+        reloaded — the default id()-based key is safe (the entry pins the
+        source image) but misses across reloads of the same content.
+        """
+        from src.adaptive_images import fit_image as _fit_image
+
+        box_w, box_h = _box_dims(box)
+        resample_name = getattr(resample, "name", repr(resample)) if resample is not None else "default"
+        identity = cache_key if cache_key is not None else ("id", id(img))
+        key = ("image", identity, img.size, box_w, box_h, mode,
+               crop_to_ink, anchor, resample_name, upscale)
+
+        cached = self._image_cache.get(key)
+        if cached is not None:
+            self._image_cache.move_to_end(key)
+            return cached[0]
+
+        result = _fit_image(img, (box_w, box_h), mode=mode,
+                            crop_to_ink=crop_to_ink, anchor=anchor,
+                            resample=resample, upscale=upscale)
+        # Pin the source only for id()-keyed entries (see docstring).
+        self._image_cache[key] = (result, img if cache_key is None else None)
+        while len(self._image_cache) > self._IMAGE_CACHE_MAX:
+            self._image_cache.popitem(last=False)
+        return result
+
+    # ---- text utilities ------------------------------------------------
+
+    def ellipsize(self, text: str, font: Any, max_w: int) -> str:
+        """Trim text to fit max_w, appending an ellipsis. Returns '' when
+        not even the ellipsis fits."""
+        if measure_ink(text, font)[0] <= max_w:
+            return text
+        for end in range(len(text) - 1, 0, -1):
+            candidate = text[:end].rstrip() + ELLIPSIS
+            if measure_ink(candidate, font)[0] <= max_w:
+                return candidate
+        return ELLIPSIS if measure_ink(ELLIPSIS, font)[0] <= max_w else ""
+
+    def measure(self, text: str, font: Any) -> Tuple[int, int, int]:
+        """Ink (width, height, baseline) of text — see measure_ink."""
+        width, height, baseline, _ = measure_ink(text, font)
+        return (width, height, baseline)
+
+    def clear_cache(self) -> None:
+        """Drop cached fit results (call after fonts are reloaded)."""
+        self._fit_cache.clear()
+        self._image_cache.clear()
+
+
+def _pick_tier(tiers: Tuple[Tuple[str, int], ...], value: int) -> str:
+    for name, limit in tiers:
+        if value <= limit:
+            return name
+    return tiers[-1][0]
+
+
+def _box_dims(box: Union[Region, Tuple[int, int]]) -> Tuple[int, int]:
+    if isinstance(box, Region):
+        return (box.w, box.h)
+    w, h = box
+    return (int(w), int(h))
+
+
+def draw_fitted_text(display_manager: Any, fit: FitResult,
+                     box: Union[Region, Tuple[int, int]],
+                     color: Tuple[int, int, int] = (255, 255, 255),
+                     align: str = "center", valign: str = "center") -> None:
+    """Draw a FitResult's text aligned within a Region via
+    DisplayManager.draw_text(), compensating for the font's ink offset so
+    the ink (not the em box) is what gets aligned."""
+    region = box if isinstance(box, Region) else Region(0, 0, box[0], box[1])
+    x, y = region.align_xy(fit.width, fit.height, align, valign)
+    display_manager.draw_text(fit.text, x=x, y=y - fit.y_offset,
+                              color=color, font=fit.font)
+
+
+# ---------------------------------------------------------------------------
+# Composite layouts — the region arrangements repeated across plugins,
+# expressed as Region math so migrated plugins stop hand-copying coordinate
+# formulas. Deliberately tiny: these return Regions, they don't draw.
+# ---------------------------------------------------------------------------
+
+@dataclass(frozen=True)
+class ScoreboardRegions:
+    """The two-logos-plus-center-score card shared by the sports plugins."""
+    bounds: Region
+    logo_slot: int        # width of each logo slot: min(H, W // 2), center-reserved
+    away_slot: Region     # left logo slot
+    home_slot: Region     # right logo slot
+    center_col: Region    # column between the slots (>= min_center_fraction of width)
+    status_band: Region   # top band (replaces the magic y = 1)
+    score_area: Region    # center_col's true width, between the bands (replaces y = H//2 - 3)
+    detail_band: Region   # bottom band (replaces the magic y = H - 7)
+    bottom_left: Region   # bottom corner: away records / timeouts
+    bottom_right: Region  # bottom corner: home records / timeouts
+
+
+def scoreboard_regions(bounds: Region, *, ctx: Optional["LayoutContext"] = None,
+                       status_h: Optional[int] = None,
+                       detail_h: Optional[int] = None,
+                       min_center_fraction: float = 0.15,
+                       min_center_design_px: int = 40,
+                       score_bleed_fraction: float = 0.5) -> ScoreboardRegions:
+    """Carve a game-card Region into the standard scoreboard arrangement.
+
+    Encodes the invariant duplicated across the sports plugins:
+    ``logo_slot = min(height, width // 2)`` (capped at half the card so the
+    home slot never collapses), away logo centered in the left slot, home in
+    the right.
+
+    That formula alone has a blind spot: at exactly 2:1 aspect ratio
+    (width == 2 * height — a very common shape, e.g. two, four, or more
+    square modules stacked into a taller panel) ``width // 2`` and
+    ``height`` are equal, so the two logo slots claim the *entire* width
+    and leave zero pixels for a center column, no matter how large the
+    panel gets. It isn't a "small panel" problem: 96x48, 128x64, and
+    256x128 (all exactly 2:1) hit it identically, while wide panels like
+    the 128x32 design baseline or a 192x48/256x32 panel never do, because
+    height is already the tighter constraint there.
+
+    Two knobs fix it, both defaulted to values verified against the full
+    harness size spread (see test_adaptive_layout.py::TestScoreboardRegions):
+
+    - ``min_center_fraction`` / ``min_center_design_px`` reserve at least
+      ``max(width * min_center_fraction, min_center_design_px * ctx.scale)``
+      for the center column, capping ``logo_slot`` further when needed. The
+      design-px term (scaled by the context's geometry factor, so it grows
+      on bigger panels like everything else in ``px()``) matters most on
+      small panels where a flat fraction alone reserves too little absolute
+      space for even a short score string. On wide panels the height
+      constraint already leaves more room than either reserves, so both are
+      a no-op there — 128x32/192x48-style layouts are unaffected.
+    - ``score_bleed_fraction`` extends the score's own *fit box* (not the
+      logo slots themselves) an extra ``logo_slot * score_bleed_fraction``
+      into each side — controlled, intentional overlap with the logo art,
+      the same way real broadcast scoreboards let a big score number's
+      edges cross into the team marks flanking it. Without this, on a
+      square-ish panel the center reserve alone can be too narrow for even
+      a modest score to render without truncating (`"17-21"` -> `"17-2…"`),
+      which is worse than a little overlap.
+
+    status_band and detail_band span the FULL card width and overlay the
+    logo slots — matching the classic layouts, where short outlined status/
+    date text is drawn over the logos without issue; only score_area (the
+    one element whose size actively grows with the panel) uses the
+    narrower, bleed-adjusted box. Band heights default to the classic
+    128x32 values, scaled by the context's geometry factor when one is
+    provided. Works on a full panel or on a scroll-mode card Region.
+    """
+    if status_h is None:
+        status_h = ctx.px(9, minimum=7) if ctx else 9
+    if detail_h is None:
+        detail_h = ctx.px(8, minimum=7) if ctx else 8
+
+    logo_slot = min(bounds.h, bounds.w // 2)
+    design_reserve = int(min_center_design_px * (ctx.scale if ctx else 1.0))
+    min_center_w = max(1, int(bounds.w * min_center_fraction), design_reserve)
+    max_logo_slot_by_center = max(1, (bounds.w - min_center_w) // 2)
+    logo_slot = min(logo_slot, max_logo_slot_by_center)
+    away_slot = bounds.left_col(logo_slot)
+    home_slot = bounds.right_col(logo_slot)
+    center_col = Region(bounds.x + logo_slot, bounds.y,
+                        bounds.w - 2 * logo_slot, bounds.h)
+    status_band = bounds.top_band(status_h)
+    detail_band = bounds.bottom_band(detail_h)
+    middle = bounds.middle(status_band.h, detail_band.h)
+    # score_area is the true center gap's width plus a controlled bleed
+    # into each logo slot (see score_bleed_fraction above) -- narrower than
+    # the full card width status/detail get, since it's the one element
+    # whose size actively grows with the panel and needs its *fit box* to
+    # reflect real available space, but generous enough that a short score
+    # string never has to truncate on a square-ish panel.
+    bleed = int(logo_slot * score_bleed_fraction)
+    score_area = Region(center_col.x - bleed, middle.y,
+                        center_col.w + 2 * bleed, middle.h)
+    bottom = bounds.bottom_band(detail_h)
+    return ScoreboardRegions(
+        bounds=bounds, logo_slot=logo_slot,
+        away_slot=away_slot, home_slot=home_slot, center_col=center_col,
+        status_band=status_band, score_area=score_area, detail_band=detail_band,
+        bottom_left=bottom.left_col(logo_slot),
+        bottom_right=bottom.right_col(logo_slot),
+    )
+
+
+@dataclass(frozen=True)
+class MediaRow:
+    """Art/icon on the left, text column on the right (music's idiom)."""
+    art: Region
+    body: Region
+
+
+def media_row(bounds: Region, *, ctx: Optional["LayoutContext"] = None,
+              square: bool = True, gap: Optional[int] = None) -> MediaRow:
+    """Split a Region into an art slot and a body column.
+
+    With ``square=True`` the art slot is bounds.h wide (album-art style);
+    otherwise it takes the left half. The gap defaults to 2px scaled by the
+    context's geometry factor.
+    """
+    if gap is None:
+        gap = ctx.px(2, minimum=1) if ctx else 2
+    art_w = bounds.h if square else bounds.w // 2
+    art_w = min(art_w, bounds.w)
+    art = bounds.left_col(art_w)
+    body = Region(bounds.x + art_w + gap, bounds.y,
+                  bounds.w - art_w - gap, bounds.h)
+    return MediaRow(art=art, body=body)

src/cache/disk_cache.py

@@ -10,6 +10,7 @@ import time
 import tempfile
 import logging
 import threading
+import zlib
 from typing import Dict, Any, Optional, Protocol
 from datetime import datetime
 
@@ -53,6 +54,11 @@ class DiskCache:
         self.cache_dir = cache_dir
         self.logger = logger or logging.getLogger(__name__)
         self._lock = threading.Lock()
+        # key -> adler32 of the last payload successfully written to the
+        # primary cache path; lets set() skip rewriting identical data
+        # (per-process only — worst case another process rewrites, never
+        # a missed write). Guarded by _lock.
+        self._write_digests: Dict[str, int] = {}
     
     def get_cache_path(self, key: str) -> Optional[str]:
         """
@@ -68,14 +74,15 @@ class DiskCache:
             return None
         return os.path.join(self.cache_dir, f"{key}.json")
     
-    def get(self, key: str, max_age: int = 300) -> Optional[Dict[str, Any]]:
+    def get(self, key: str, max_age: Optional[int] = 300) -> Optional[Dict[str, Any]]:
         """
         Get data from disk cache.
-        
+
         Args:
             key: Cache key
-            max_age: Maximum age in seconds
-            
+            max_age: Maximum age in seconds; None disables age-based expiry
+                (the record never counts as stale). Mirrors MemoryCache.get.
+
         Returns:
             Cached data or None if not found or expired
         """
@@ -105,7 +112,13 @@ class DiskCache:
                     record_ts = None
             
             now = time.time()
-            if record_ts is None or (now - record_ts) <= max_age:
+            # max_age=None means "never expires" (mirrors MemoryCache and the
+            # cache_manager docstring). Guard it explicitly — otherwise the
+            # comparison below raises TypeError and the record is treated as a
+            # miss, which silently breaks callers that persist long-lived state
+            # via get(key, max_age=None) (e.g. plugin health/metrics that must
+            # survive restarts and be read cross-process).
+            if record_ts is None or max_age is None or (now - record_ts) <= max_age:
                 return record
             else:
                 # Stale on disk; keep file for potential diagnostics but treat as miss
@@ -148,10 +161,35 @@ class DiskCache:
         cache_path = self.get_cache_path(key)
         if not cache_path:
             return
-        
+
+        # Serialize once, compact (no indent): the payload is reused by every
+        # write path below, and cache files are machine-read only — indenting
+        # them just multiplied the bytes written to the SD card.
+        try:
+            payload = json.dumps(data, cls=DateTimeEncoder)
+        except (TypeError, ValueError) as e:
+            self.logger.warning("Cache data for key '%s' not serializable: %s", key, e)
+            return
+
+        digest = zlib.adler32(payload.encode('utf-8'))
+
         try:
             # Atomic write to avoid partial/corrupt files
             with self._lock:
+                # Skip the disk entirely when this exact payload was already
+                # written for this key (plugins re-save unchanged API data
+                # every update cycle — each write is real SD-card wear).
+                # Refresh the file mtime so records that rely on it for TTL
+                # (no embedded 'timestamp') don't expire early; a metadata
+                # touch is journal-cheap compared to rewriting the data.
+                if self._write_digests.get(key) == digest:
+                    try:
+                        os.utime(cache_path, None)
+                        return
+                    except OSError:
+                        # File vanished or perms changed — fall through and write
+                        self._write_digests.pop(key, None)
+
                 tmp_dir = os.path.dirname(cache_path)
                 # Try to create temp file in cache directory first
                 # If that fails due to permissions, fall back to direct write
@@ -174,13 +212,17 @@ class DiskCache:
                         fd = None
                     
                     if tmp_path and fd is not None:
-                        # Use atomic write with temp file
+                        # Atomic write with temp file. No fsync: os.replace
+                        # already guarantees readers never see a torn file,
+                        # and cache data is re-fetchable — forcing a disk
+                        # flush per write was the single biggest SD-card
+                        # wear source (dozens of fsyncs/min on API-heavy
+                        # installs) for data that can be re-downloaded.
                         try:
                             with os.fdopen(fd, 'w', encoding='utf-8') as tmp_file:
-                                json.dump(data, tmp_file, indent=4, cls=DateTimeEncoder)
-                                tmp_file.flush()
-                                os.fsync(tmp_file.fileno())
+                                tmp_file.write(payload)
                             os.replace(tmp_path, cache_path)
+                            self._write_digests[key] = digest
                             # Set proper permissions: 660 (rw-rw----) for group-readable cache files
                             try:
                                 os.chmod(cache_path, 0o660)  # nosec B103 - intentional; web UI and service share a group
@@ -196,9 +238,8 @@ class DiskCache:
                         # Fallback: direct write (not atomic, but better than failing)
                         try:
                             with open(cache_path, 'w', encoding='utf-8') as cache_file:
-                                json.dump(data, cache_file, indent=4, cls=DateTimeEncoder)
-                                cache_file.flush()
-                                os.fsync(cache_file.fileno())
+                                cache_file.write(payload)
+                            self._write_digests[key] = digest
                             # Set proper permissions: 660 (rw-rw----) for group-readable cache files
                             try:
                                 os.chmod(cache_path, 0o660)  # nosec B103 - intentional; web UI and service share a group
@@ -222,9 +263,12 @@ class DiskCache:
                             pass
                         
                         if os.path.isdir(fallback_dir) and os.access(fallback_dir, os.W_OK):
+                            # NOTE: no digest record here — the fallback file
+                            # is a different path, so future sets must keep
+                            # retrying the primary location.
                             fallback_path = os.path.join(fallback_dir, os.path.basename(cache_path))
                             with open(fallback_path, 'w', encoding='utf-8') as tmp_file:
-                                json.dump(data, tmp_file, indent=4, cls=DateTimeEncoder)
+                                tmp_file.write(payload)
                             # Set proper permissions: 660 (rw-rw----) for group-readable cache files
                             try:
                                 os.chmod(fallback_path, 0o660)  # nosec B103 - intentional; web UI and service share a group
@@ -265,6 +309,7 @@ class DiskCache:
         
         with self._lock:
             if key:
+                self._write_digests.pop(key, None)
                 cache_path = self.get_cache_path(key)
                 if cache_path and os.path.exists(cache_path):
                     try:
@@ -273,6 +318,7 @@ class DiskCache:
                         self.logger.warning("Could not remove cache file %s: %s", cache_path, e)
             else:
                 # Clear all cache files
+                self._write_digests.clear()
                 if os.path.exists(self.cache_dir):
                     for filename in os.listdir(self.cache_dir):
                         if filename.endswith('.json'):

src/cache_manager.py

@@ -574,9 +574,19 @@ class CacheManager:
         }
         return self.save_cache(data_type, cache_data)
 
-    def get(self, key: str, max_age: int = 300) -> Optional[Dict[str, Any]]:
-        """Get data from cache if it exists and is not stale."""
-        cached_data = self.get_cached_data(key, max_age)
+    def get(self, key: str, max_age: Optional[int] = 300,
+            memory_ttl: Optional[int] = None) -> Optional[Dict[str, Any]]:
+        """Get data from cache if it exists and is not stale.
+
+        Args:
+            key: Cache key
+            max_age: Max age (seconds) for the on-disk entry; None never expires.
+            memory_ttl: Max age (seconds) for the in-memory entry. Pass 0 to
+                bypass the memory tier and force a fresh read from disk — used by
+                cross-process readers that must observe another process's latest
+                write rather than a stale first snapshot. Defaults to max_age.
+        """
+        cached_data = self.get_cached_data(key, max_age, memory_ttl=memory_ttl)
         if cached_data and 'data' in cached_data:
             return cached_data['data']
         return cached_data

src/common/README.md

@@ -2,6 +2,28 @@
 
 This directory contains reusable utilities and helpers for LEDMatrix plugins and core modules.
 
+## Adaptive Layout & Images (`src/adaptive_layout.py`, `src/adaptive_images.py`)
+
+The recommended way to lay out plugins that render legibly on **any** panel
+size (64x32 through 256x128+) without hand-tuned coordinates. Re-exported
+from `src.common` for convenience; canonical import paths are
+`src.adaptive_layout` / `src.adaptive_images`.
+
+```python
+# Every BasePlugin already has self.layout and the draw helpers:
+regs = scoreboard_regions(self.layout.bounds, ctx=self.layout)
+self.draw_image(away_logo, regs.away_slot, mode="fill_height",
+                crop_to_ink=True, cache_key=f"logo:{abbr}")
+self.draw_fit(score_text, regs.score_area)     # largest crisp font that fits
+self.draw_fit(status, regs.status_band)
+```
+
+Key pieces: `Region` (rect algebra: bands/columns/splits/offset),
+font ladders (`LADDER_GRID`, `LADDER_ARCADE` — discrete crisp sizes, never
+fractional scaling), `LayoutContext` (`fit_text`, `fit_image`, `by_tier`,
+`px`), and composite carvers `scoreboard_regions()` / `media_row()`.
+Full guide: [docs/ADAPTIVE_LAYOUT.md](../../docs/ADAPTIVE_LAYOUT.md).
+
 ## Error Handling (`error_handler.py`)
 
 Common error handling patterns and utilities:

src/common/__init__.py

@@ -26,6 +26,31 @@ from src.common.scroll_helper import ScrollHelper
 from src.common.logo_helper import LogoHelper
 from src.common.text_helper import TextHelper
 
+# Adaptive layout & images (canonical homes: src.adaptive_layout /
+# src.adaptive_images — re-exported here so plugin authors find them in the
+# blessed-helpers package). See docs/ADAPTIVE_LAYOUT.md.
+from src.adaptive_layout import (
+    Region,
+    LayoutContext,
+    FontStep,
+    FontLadder,
+    LADDER_GRID,
+    LADDER_ARCADE,
+    FitResult,
+    draw_fitted_text,
+    ScoreboardRegions,
+    scoreboard_regions,
+    MediaRow,
+    media_row,
+)
+from src.adaptive_images import (
+    ImageFitResult,
+    fit_image,
+    draw_fitted_image,
+    RESAMPLE_LANCZOS,
+    RESAMPLE_NEAREST,
+)
+
 __all__ = [
     'handle_file_operation',
     'handle_json_operation',
@@ -37,4 +62,22 @@ __all__ = [
     'ScrollHelper',
     'LogoHelper',
     'TextHelper',
+    # adaptive layout & images
+    'Region',
+    'LayoutContext',
+    'FontStep',
+    'FontLadder',
+    'LADDER_GRID',
+    'LADDER_ARCADE',
+    'FitResult',
+    'draw_fitted_text',
+    'ScoreboardRegions',
+    'scoreboard_regions',
+    'MediaRow',
+    'media_row',
+    'ImageFitResult',
+    'fit_image',
+    'draw_fitted_image',
+    'RESAMPLE_LANCZOS',
+    'RESAMPLE_NEAREST',
 ]

src/common/logo_helper.py

@@ -72,9 +72,20 @@ class LogoHelper:
             
         Returns:
             PIL Image object or None if loading fails
+
+        Note: for new adaptive-layout code prefer ``BasePlugin.draw_image``
+        / ``LayoutContext.fit_image`` (src/adaptive_images.py) for the
+        fitting step — LogoHelper remains useful for its download and
+        placeholder logic.
         """
-        # Check cache first
-        cache_key = f"{team_abbr}_{logo_path}"
+        # Resolve the effective target size BEFORE the cache lookup so the
+        # key is size-qualified — a panel-size change must not return a
+        # logo resized for the old dimensions.
+        if max_width is None:
+            max_width = int(self.display_width * 1.5)
+        if max_height is None:
+            max_height = int(self.display_height * 1.5)
+        cache_key = f"{team_abbr}_{logo_path}_{max_width}x{max_height}"
         if cache_key in self._logo_cache:
             self.logger.debug(f"Using cached logo for {team_abbr}")
             # Update LRU order (move to end)

src/common/permission_utils.py

@@ -8,13 +8,34 @@ files that need to be accessible by both root service and web user.
 
 import os
 import logging
+import re
 import shutil as _shutil
 import subprocess
+import sys
 from pathlib import Path
 from typing import Optional
 
 logger = logging.getLogger(__name__)
 
+# Matches the credentials portion of a "scheme://user:pass@host" URL, so pip's
+# own error output can be logged/displayed without echoing back a private
+# index URL's embedded basic-auth secret verbatim (e.g. from a
+# requirements.txt --index-url line or the PIP_INDEX_URL env var).
+_URL_CREDENTIALS_RE = re.compile(r'://[^/\s@:]+:[^/\s@]+@')
+
+
+def _redact_url_credentials(text: Optional[str]) -> str:
+    """Replace embedded user:pass@ URL credentials in text with a placeholder.
+
+    Safe to call on any subprocess output destined for logs: it only ever
+    shortens/replaces the credential substring, never changes the presence
+    or absence of the specific fixed phrases callers check for
+    (e.g. "a password is required"), so it can't affect control flow.
+    """
+    if not text:
+        return text or ""
+    return _URL_CREDENTIALS_RE.sub('://***:***@', text)
+
 # System directories that should never have their permissions modified
 # These directories have special system-level permissions that must be preserved
 PROTECTED_SYSTEM_DIRECTORIES = {  # nosec B108 - these are checked to PREVENT permission changes, not to use as temp paths
@@ -287,3 +308,119 @@ def sudo_remove_directory(path: Path, allowed_bases: Optional[list] = None) -> b
         logger.error(f"Unexpected error during sudo helper for {path}: {e}")
         return False
 
+
+def install_requirements_file(req_file: Path, timeout: int = 300) -> subprocess.CompletedProcess:
+    """
+    Install a requirements.txt file for a plugin (or the project itself).
+
+    Prefers the vetted sudo wrapper (scripts/fix_perms/safe_pip_install.sh) so
+    packages end up visible to root-run ledmatrix.service, not just to
+    whichever non-root user happens to run the calling process (e.g. the web
+    interface). Falls back to installing with the calling process's own
+    interpreter if the wrapper isn't set up yet (the admin hasn't run
+    scripts/install/configure_web_sudo.sh), so dependency installation still
+    does *something* useful rather than hard-failing.
+
+    Always installs with the interpreter that will actually run the code
+    (``sys.executable`` in the fallback path, the wrapper's ``python3`` in the
+    sudo path) rather than a bare ``pip``/``pip3`` off PATH, which can
+    silently resolve to a different Python installation (e.g. system Python
+    vs. a virtualenv) than the one importing the package at runtime.
+
+    Args:
+        req_file: Path to a requirements.txt file
+        timeout: Subprocess timeout in seconds
+
+    Returns:
+        subprocess.CompletedProcess from the pip (or wrapper) invocation.
+        Never raises on a non-zero exit; callers should check ``returncode``.
+        ``stdout`` is prefixed with an explanatory note when the root wrapper
+        was unavailable and the fallback path was used.
+    """
+    project_root = Path(__file__).resolve().parent.parent.parent
+    wrapper = project_root / "scripts" / "fix_perms" / "safe_pip_install.sh"
+
+    if wrapper.exists():
+        # See sudo_remove_directory / configure_web_sudo.sh for why bash must
+        # be invoked with an explicit, known path rather than relying on the
+        # wrapper's shebang: sudoers matches the exact command line.
+        bash_candidates = []
+        for candidate in ("/usr/bin/bash", "/bin/bash", _shutil.which("bash")):
+            if candidate and candidate not in bash_candidates:
+                bash_candidates.append(candidate)
+
+        result = None
+        for bash_path in bash_candidates:
+            # bash_path and wrapper are fixed, known-good paths, and
+            # safe_pip_install.sh independently re-validates req_file is an
+            # allowed requirements.txt before installing anything as root.
+            result = subprocess.run(  # nosec B603 - no shell invoked (list-form argv)  # nosemgrep
+                ["sudo", "-n", bash_path, str(wrapper), str(req_file)],
+                capture_output=True, text=True, timeout=timeout, cwd=str(project_root)
+            )
+            # Redact immediately: pip can echo a private index URL's embedded
+            # basic-auth credentials back in its own error/progress output
+            # (e.g. from a requirements.txt --index-url line). Doesn't affect
+            # the fixed-phrase "denied" check below -- those phrases never
+            # overlap with URL syntax.
+            result.stderr = _redact_url_credentials(result.stderr)
+            result.stdout = _redact_url_credentials(result.stdout)
+            if result.returncode == 0:
+                return result
+            # Distinguish "sudo rejected this exact command line" (worth
+            # trying the next bash candidate) from "sudo ran it but pip
+            # itself failed" (a real error — stop and surface it).
+            denied = any(
+                phrase in result.stderr
+                for phrase in ("a password is required", "is not allowed to run", "no tty present")
+            )
+            if not denied:
+                # Deliberately don't interpolate req_file or the pip output here:
+                # this log line is scanner-visible, and a static analyzer can't
+                # tell "already redacted above" from "still raw" just by looking
+                # at this call in isolation. The full (redacted) text is still
+                # available to callers via the returned CompletedProcess.
+                logger.warning(
+                    "Root pip install failed (rc=%s); see the returned "
+                    "CompletedProcess.stderr for details.",
+                    result.returncode,
+                )
+                return result
+
+        # Same reasoning as above: no req_file / pip-output interpolation in
+        # this log line, only in the returned note/CompletedProcess.
+        logger.warning(
+            "Root pip install wrapper denied via sudo for all candidates; "
+            "falling back to user-level install. See the returned "
+            "CompletedProcess.stderr for details."
+        )
+        note = (
+            f"[Root install unavailable ({(result.stderr.strip() if result else 'sudo denied') or 'sudo denied'}); "
+            "installed for the current process's user only. Packages may not be "
+            "visible to ledmatrix.service if it runs as a different user — "
+            "run scripts/install/configure_web_sudo.sh to fix this.]\n"
+        )
+    else:
+        logger.warning(
+            "safe_pip_install.sh not found; falling back to user-level install."
+        )
+        note = (
+            "[safe_pip_install.sh not found; installed for the current process's "
+            "user only. Run scripts/install/configure_web_sudo.sh to enable "
+            "root installs visible to ledmatrix.service.]\n"
+        )
+
+    # sys.executable is this process's own interpreter (not
+    # attacker-influenced), and req_file is a Path built internally by callers
+    # (store_manager.py plugin paths, PROJECT_ROOT/requirements.txt), never
+    # raw external/user input. --ignore-installed matches safe_pip_install.sh:
+    # apt-managed packages (e.g. python3-requests) ship no pip RECORD file, so
+    # upgrading them would otherwise abort with "uninstall-no-record-file".
+    result = subprocess.run(  # nosec B603 - no shell invoked (list-form argv)  # nosemgrep
+        [sys.executable, "-m", "pip", "install", "--break-system-packages", "--ignore-installed", "-r", str(req_file)],
+        capture_output=True, text=True, timeout=timeout, cwd=str(project_root)
+    )
+    result.stderr = _redact_url_credentials(result.stderr)
+    result.stdout = note + _redact_url_credentials(result.stdout)
+    return result
+

src/common/snapshot_policy.py

@@ -0,0 +1,68 @@
+"""Snapshot write policy for the display preview mirror.
+
+The display service mirrors frames to /tmp/led_matrix_preview.png, which
+serves two consumers with different needs:
+
+- The web UI's live preview (SSE reader in web_interface/app.py) wants
+  fresh frames — but only while a browser is actually watching.
+- The health check (web_interface/blueprints/api_v3.py, hardware status)
+  uses the file's AGE as a liveness proxy: age >= 60s reads as degraded.
+
+PNG-encoding every frame at 5 fps forever — identical frames, no viewers —
+was one of the biggest fixed CPU costs on the Pi. This module is the pure
+decision logic (extracted so it's unit-testable off-Pi; display_manager
+imports rgbmatrix unconditionally and can't be):
+
+    WRITE  — encode + atomically replace the snapshot file
+    TOUCH  — os.utime only: keeps the health-check mtime fresh and lets
+             the SSE reader (mtime-gated) resend at a low rate, without
+             paying for a PNG encode of an unchanged frame
+    SKIP   — do nothing
+
+Policy:
+- With a fresh viewer marker: changed frames write at up to 1/VIEWER_INTERVAL.
+- Without viewers: changed frames still write at 1/IDLE_INTERVAL so the
+  preview page shows something recent on open.
+- Unchanged frames are never re-encoded; the mtime is touched every
+  TOUCH_INTERVAL so the health check (60s threshold) never degrades.
+
+If any constant here changes, re-check the health threshold in
+api_v3.py (get_hardware_status) — TOUCH_INTERVAL must stay well under it.
+"""
+
+from enum import Enum
+
+# Snapshot cadence with a browser preview open (seconds).
+VIEWER_INTERVAL = 0.2
+# Snapshot cadence with no viewers — cheap freshness for page-open (seconds).
+IDLE_INTERVAL = 30.0
+# Max age of the last write/touch before bumping mtime for the health
+# check. MUST stay well under api_v3's 60s degraded threshold.
+TOUCH_INTERVAL = 20.0
+# A viewer marker older than this no longer counts as a live viewer.
+VIEWER_MARKER_FRESH_SEC = 5.0
+
+
+class SnapshotAction(Enum):
+    WRITE = "write"
+    TOUCH = "touch"
+    SKIP = "skip"
+
+
+def decide(now: float, last_write_ts: float, last_touch_ts: float,
+           viewer_fresh: bool, frame_changed: bool) -> SnapshotAction:
+    """Decide what to do with the current frame.
+
+    Args:
+        now: current monotonic-ish timestamp (same clock as the ts args)
+        last_write_ts: when a frame was last actually encoded+written
+        last_touch_ts: when the file mtime was last bumped (write or touch)
+        viewer_fresh: a browser preview is currently watching
+        frame_changed: the frame differs from the last WRITTEN frame
+    """
+    interval = VIEWER_INTERVAL if viewer_fresh else IDLE_INTERVAL
+    if frame_changed and (now - last_write_ts) >= interval:
+        return SnapshotAction.WRITE
+    if (now - max(last_write_ts, last_touch_ts)) >= TOUCH_INTERVAL:
+        return SnapshotAction.TOUCH
+    return SnapshotAction.SKIP

src/common/text_helper.py

@@ -11,6 +11,9 @@ from typing import Dict, List, Optional, Tuple, Union
 
 from PIL import Image, ImageDraw, ImageFont
 
+# Shared throwaway draw surface for measuring text without a target canvas.
+_measure_draw = ImageDraw.Draw(Image.new("RGB", (1, 1)))
+
 
 class TextHelper:
     """
@@ -112,10 +115,10 @@ class TextHelper:
             Width in pixels
         """
         try:
-            return draw.textlength(text, font=font)
+            return int(_measure_draw.textlength(text, font=font))
         except AttributeError:
             # Fallback for older PIL versions
-            bbox = draw.textbbox((0, 0), text, font=font)
+            bbox = _measure_draw.textbbox((0, 0), text, font=font)
             return bbox[2] - bbox[0]
     
     def get_text_height(self, text: str, font: ImageFont.ImageFont) -> int:
@@ -129,13 +132,8 @@ class TextHelper:
         Returns:
             Height in pixels
         """
-        try:
-            bbox = draw.textbbox((0, 0), text, font=font)
-            return bbox[3] - bbox[1]
-        except AttributeError:
-            # Fallback for older PIL versions
-            bbox = draw.textbbox((0, 0), text, font=font)
-            return bbox[3] - bbox[1]
+        bbox = _measure_draw.textbbox((0, 0), text, font=font)
+        return bbox[3] - bbox[1]
     
     def get_text_dimensions(self, text: str, font: ImageFont.ImageFont) -> Tuple[int, int]:
         """

src/config_manager.py

@@ -56,6 +56,13 @@ class ConfigManager:
         self.secrets_path: str = secrets_path or "config/config_secrets.json"
         self.template_path: str = "config/config.template.json"
         self.config: Dict[str, Any] = {}
+        # (mtime_ns, size) signature of (config, secrets, template) at the
+        # last successful load. load_config() skips the full re-read (3 file
+        # parses + recursive template migration) when nothing changed —
+        # ~30 web request handlers call it, some 2-3x per request. Cross-
+        # process freshness is preserved: another process's save bumps the
+        # mtime, so the next load here re-reads.
+        self._loaded_sig: Optional[tuple] = None
         self.logger: logging.Logger = get_logger(__name__)
         
         # Initialize atomic config manager
@@ -122,6 +129,14 @@ class ConfigManager:
         # Update in-memory config if save was successful
         if result.status == SaveResultStatus.SUCCESS:
             self.config = new_config_data
+            # In-memory config now matches what was just written; refresh
+            # the load signature so the fast path stays valid. NOTE: the
+            # in-memory copy includes merged secrets; the on-disk file has
+            # them stripped — the fast path returning self.config preserves
+            # exactly the pre-cache behavior (load-after-save also returned
+            # the secret-merged self.config only after re-reading secrets;
+            # here secrets file is unchanged, so contents are equivalent).
+            self._loaded_sig = self._files_signature()
             self.logger.info(f"Configuration successfully saved atomically to {os.path.abspath(self.config_path)}")
         elif result.status == SaveResultStatus.ROLLED_BACK:
             # Reload config from file after rollback
@@ -179,13 +194,36 @@ class ConfigManager:
         atomic_mgr = self._get_atomic_manager()
         return atomic_mgr.validate_config_file(config_path)
 
+    def _files_signature(self) -> tuple:
+        """(mtime_ns, size) of config/secrets/template, None for missing —
+        cheap staleness probe (3 stats) for the load_config fast path."""
+        sig = []
+        for path in (self.config_path, self.secrets_path, self.template_path):
+            try:
+                st = os.stat(path)
+                sig.append((st.st_mtime_ns, st.st_size))
+            except OSError:
+                sig.append(None)
+        return tuple(sig)
+
     def load_config(self) -> Dict[str, Any]:
-        """Load configuration from JSON files."""
+        """Load configuration from JSON files.
+
+        Fast path: when config.json, config_secrets.json and the template
+        are all unchanged since the last successful load (mtime_ns + size),
+        the already-parsed self.config is returned without touching the
+        files — same aliasing semantics as the full path, which also
+        returns self.config.
+        """
         try:
+            current_sig = self._files_signature()
+            if self.config and self._loaded_sig == current_sig:
+                return self.config
+
             # Check if config file exists, if not create from template
             if not os.path.exists(self.config_path):
                 self._create_config_from_template()
-            
+
             # Load main config
             self.logger.info(f"Attempting to load config from: {os.path.abspath(self.config_path)}")
             with open(self.config_path, 'r') as f:
@@ -205,7 +243,10 @@ class ConfigManager:
                     self.logger.warning(f"Secrets file not readable ({self.secrets_path}): {e}. Continuing without secrets.")
                 except (json.JSONDecodeError, OSError) as e:
                     self.logger.warning(f"Error reading secrets file ({self.secrets_path}): {e}. Continuing without secrets.")
-            
+
+            # Signature taken AFTER load + migration (migration may write the
+            # config back), so it reflects exactly what was read/written.
+            self._loaded_sig = self._files_signature()
             return self.config
             
         except FileNotFoundError as e:
@@ -264,7 +305,8 @@ class ConfigManager:
                 json.dump(config_to_write, f, indent=4)
             
             # Update the in-memory config to the new state (which includes secrets for runtime)
-            self.config = new_config_data 
+            self.config = new_config_data
+            self._loaded_sig = self._files_signature()
             self.logger.info(f"Configuration successfully saved to {os.path.abspath(self.config_path)}")
             if secrets_content:
                  self.logger.info("Secret values were preserved in memory and not written to the main config file.")

src/display_controller.py

@@ -23,8 +23,11 @@ Entry point: :func:`main` — instantiates :class:`DisplayController` and calls
 import time
 import os
 import json
+import threading
+import types
+from contextlib import contextmanager
 from pathlib import Path
-from typing import Dict, Any, List, Optional
+from typing import Dict, Any, List, Optional, Callable
 from datetime import datetime
 from concurrent.futures import ThreadPoolExecutor, as_completed  # pylint: disable=no-name-in-module
 import pytz
@@ -163,6 +166,13 @@ class DisplayController:
         self.plugin_modes = {}  # mode -> plugin_instance mapping for plugin-first dispatch
         self.mode_to_plugin_id: Dict[str, str] = {}
         self.plugin_display_modes: Dict[str, List[str]] = {}
+        # Per-plugin config-change callbacks, kept so we can unsubscribe a
+        # plugin when it is disabled live.
+        self._plugin_config_callbacks: Dict[str, Callable] = {}
+        # Set by the config-watcher thread when the enabled-plugin set changes;
+        # the main run loop reconciles (loads/unloads) on its own thread so
+        # mutating available_modes never races with rendering.
+        self._pending_plugin_reconcile = False
         self.on_demand_active = False
         self.on_demand_mode: Optional[str] = None
         self.on_demand_modes: List[str] = []  # All modes for the on-demand plugin
@@ -192,6 +202,10 @@ class DisplayController:
         self.wifi_status_file = WIFI_STATUS_FILE
         self.wifi_status_active = False
         self.wifi_status_expires_at: Optional[float] = None
+        # _check_wifi_status_message throttle state (checked at frame rate,
+        # stat'd at most once per second)
+        self._wifi_status_check_ts = 0.0
+        self._wifi_status_last_result: Optional[Dict[str, Any]] = None
 
         # Plugin display() signature cache — must be initialised before the plugin
         # loading loop below so the .pop() invalidation at load time is always safe.
@@ -223,7 +237,24 @@ class DisplayController:
                 cache_manager=self.cache_manager,
                 font_manager=self.font_manager
             )
-            
+
+            # Activate the plugin health/metrics subsystem. PluginManager leaves
+            # health_tracker/resource_monitor as None by default; wiring real
+            # instances here turns on the circuit breaker (a repeatedly-failing
+            # plugin's update() is skipped after consecutive failures, then
+            # retried after a cooldown) and per-plugin execution-time metrics.
+            # Both persist to the shared cache so the web UI can surface them.
+            # Done before discovery/loading so load-time schema warnings have a
+            # tracker to record against.
+            try:
+                from src.plugin_system.plugin_health import PluginHealthTracker
+                from src.plugin_system.resource_monitor import PluginResourceMonitor
+                self.plugin_manager.health_tracker = PluginHealthTracker(self.cache_manager)
+                self.plugin_manager.resource_monitor = PluginResourceMonitor(self.cache_manager)
+                logger.info("Plugin health tracking and resource monitoring enabled")
+            except Exception as e:
+                logger.warning("Could not enable plugin health/resource monitoring: %s", e)
+
             # Validate plugins after plugin manager is created
             try:
                 from src.startup_validator import StartupValidator
@@ -331,47 +362,10 @@ class DisplayController:
                         logger.info("✓ Loaded plugin %s in %.3f seconds (%d/%d)", 
                                   plugin_id, result['load_time'], loaded_count, enabled_count)
                         
-                        # Get plugin instance and manifest
-                        plugin_instance = self.plugin_manager.get_plugin(plugin_id)
-                        manifest = self.plugin_manager.plugin_manifests.get(plugin_id, {})
-                        
-                        # Prefer plugin's modes attribute if available (dynamic based on enabled leagues)
-                        # Fall back to manifest display_modes if plugin doesn't provide modes
-                        if plugin_instance and hasattr(plugin_instance, 'modes') and plugin_instance.modes:
-                            display_modes = list(plugin_instance.modes)
-                            logger.debug("Using plugin.modes for %s: %s", plugin_id, display_modes)
-                        else:
-                            display_modes = manifest.get('display_modes', [plugin_id])
-                            logger.debug("Using manifest display_modes for %s: %s", plugin_id, display_modes)
-                        
-                        if isinstance(display_modes, list) and display_modes:
-                            self.plugin_display_modes[plugin_id] = list(display_modes)
-                        else:
-                            display_modes = [plugin_id]
-                            self.plugin_display_modes[plugin_id] = list(display_modes)
-                        
-                        # Subscribe plugin to config changes for hot-reload
-                        if hasattr(self, 'config_service') and hasattr(plugin_instance, 'on_config_change'):
-                            def config_change_callback(old_config: Dict[str, Any], new_config: Dict[str, Any]) -> None:
-                                """Callback for plugin config changes."""
-                                try:
-                                    plugin_instance.on_config_change(new_config)
-                                    logger.debug("Plugin %s notified of config change", plugin_id)
-                                except Exception as e:
-                                    logger.error("Error in plugin %s config change handler: %s", plugin_id, e, exc_info=True)
-                            
-                            self.config_service.subscribe(config_change_callback, plugin_id=plugin_id)
-                            logger.debug("Subscribed plugin %s to config changes", plugin_id)
-                        
-                        # Add plugin modes to available modes
-                        for mode in display_modes:
-                            self.available_modes.append(mode)
-                            self.plugin_modes[mode] = plugin_instance
-                            self.mode_to_plugin_id[mode] = plugin_id
-                            logger.debug("  Added mode: %s", mode)
-                        # Invalidate signature cache so the new instance is re-inspected
-                        self._plugin_accepts_display_mode.pop(plugin_id, None)
-                        
+                        # Register the loaded plugin's modes, config subscription
+                        # and dispatch maps (shared with live enable hot-reload).
+                        self._register_loaded_plugin(plugin_id)
+
                         # Show progress
                         progress_pct = int((loaded_count / enabled_count) * 100)
                         elapsed = time.time() - plugin_time
@@ -447,6 +441,10 @@ class DisplayController:
         # when the user saves settings via the web UI.
         def _controller_config_change(old_config: Dict[str, Any], new_config: Dict[str, Any]) -> None:
             self._refresh_config_cache(new_config)
+            # If a plugin was enabled/disabled, flag a reconcile for the main
+            # loop to apply (loading/unloading off the watcher thread is unsafe).
+            if self._enabled_set_changed(old_config, new_config):
+                self._pending_plugin_reconcile = True
 
         self.config_service.subscribe(_controller_config_change)
 
@@ -511,7 +509,10 @@ class DisplayController:
 
             # Run plugin updates inside the Vegas loop so the inter-iteration
             # gap is <1 ms (nothing left for _tick_plugin_updates() to do).
-            self.vegas_coordinator.set_update_callback(self._tick_plugin_updates)
+            # Use the Vegas-aware variant so plugins that got fresh data are
+            # hot-swapped into the scroll promptly instead of waiting for the
+            # next full cycle.
+            self.vegas_coordinator.set_update_callback(self._tick_plugin_updates_for_vegas)
 
             # Wire multi-display sync into Vegas render pipeline
             follower_pos = self.config.get("sync", {}).get("follower_position", "left")
@@ -630,18 +631,28 @@ class DisplayController:
 
         current_day = current_time.strftime('%A').lower()  # e.g. 'monday'
         current_time_only = current_time.time()
-        
+
         # Check if per-day schedule is configured
         days_config = schedule_config.get('days')
-        
-        # Determine which schedule to use
+
+        # Determine which schedule to use. Respect an explicit 'mode' field
+        # (like the dim schedule does) so a stray/legacy 'days' dict left over
+        # from config migration or a prior per-day setup can't silently
+        # override a user's Global schedule selection.
+        mode = schedule_config.get('mode')
+        mode_normalized = mode.replace('_', '-') if mode else None
+
         use_per_day = False
-        if days_config:
-            # Check if days dict is not empty and contains current day
-            if days_config and current_day in days_config:
+        if mode_normalized == 'global':
+            use_per_day = False
+        elif mode_normalized == 'per-day':
+            use_per_day = bool(days_config and current_day in days_config)
+        elif days_config:
+            # No explicit mode recorded (legacy config) - fall back to
+            # inferring from presence of a 'days' dict for the current day.
+            if current_day in days_config:
                 use_per_day = True
-            elif days_config:
-                # Days dict exists but doesn't have current day - fall back to global
+            else:
                 logger.debug("Per-day schedule exists but %s not configured, using global schedule", current_day)
         
         if use_per_day:
@@ -837,6 +848,42 @@ class DisplayController:
                     if hasattr(self.plugin_manager, 'health_tracker') and self.plugin_manager.health_tracker:
                         self.plugin_manager.health_tracker.record_failure(plugin_id, exc)
 
+    def _tick_plugin_updates_for_vegas(self) -> None:
+        """Run scheduled plugin updates and tell Vegas mode which plugins
+        actually got fresh data, so it can hot-swap them into the scroll
+        without waiting for a full cycle to complete.
+
+        Used as the Vegas coordinator's update callback instead of the plain
+        _tick_plugin_updates() so that a live score change is reflected in
+        the ticker within a few seconds rather than at the next cycle
+        boundary (which, depending on min/max_cycle_duration, can be
+        minutes away). Restores wiring that PR #299 added and PR #330's
+        sync-mode refactor inadvertently dropped: coordinator.mark_plugin_updated()
+        has been unreachable dead code since.
+
+        Delegates the before/after plugin_last_update snapshot to
+        PluginManager.run_scheduled_updates_with_changes() so the snapshot,
+        update pass, and diff are lock-protected against this callback's own
+        background update-tick thread racing the main render loop.
+        """
+        if not self.plugin_manager or not hasattr(self.plugin_manager, "run_scheduled_updates_with_changes"):
+            self._tick_plugin_updates()
+            return
+
+        updated = self.plugin_manager.run_scheduled_updates_with_changes()
+
+        vc = getattr(self, "vegas_coordinator", None)
+        if vc is None:
+            return
+
+        if updated:
+            logger.info("Vegas update tick: %d plugin(s) updated: %s", len(updated), updated)
+            for plugin_id in updated:
+                try:
+                    vc.mark_plugin_updated(plugin_id)
+                except Exception:  # pylint: disable=broad-except
+                    logger.exception("Error marking plugin %s updated for Vegas", plugin_id)
+
     def _tick_plugin_updates(self):
         """Run scheduled plugin updates if the plugin manager supports them."""
         if not self.plugin_manager:
@@ -848,6 +895,30 @@ class DisplayController:
             except Exception:  # pylint: disable=broad-except
                 logger.exception("Error running scheduled plugin updates")
 
+    @contextmanager
+    def _display_lock_or_skip(self, plugin_id):
+        """Try-lock guard keeping a plugin's display() off its in-flight update().
+
+        Yields True when display may run (lock held, released on exit) or
+        when no lock support exists (older plugin manager). Yields False when
+        the plugin's update() is currently executing on the background
+        worker — the caller should treat the frame as displayed (the panel
+        holds the last pushed frame) rather than as a plugin failure, so a
+        mid-update skip never advances the rotation.
+        """
+        pm = self.plugin_manager
+        if not pm or not hasattr(pm, 'get_plugin_lock') or not plugin_id:
+            yield True
+            return
+        lock = pm.get_plugin_lock(plugin_id)
+        if not lock.acquire(blocking=False):
+            yield False
+            return
+        try:
+            yield True
+        finally:
+            lock.release()
+
     _FOLLOWER_SEND_INTERVAL = 1.0 / 90  # raw bytes are cheap; 90fps > follower render rate
 
     def _follower_rebuild_scroll_image(self) -> None:
@@ -1571,10 +1642,11 @@ class DisplayController:
     def run(self):
         """Run the display controller, switching between displays."""
         if not self.available_modes:
-            logger.warning("No display modes are enabled. Exiting.")
-            self.display_manager.cleanup()
-            return
-             
+            logger.warning(
+                "No display modes are enabled at startup; idling until a "
+                "plugin is enabled via the web UI."
+            )
+
         try:
             # Initialize with cached data for fast startup - let background updates refresh naturally
             logger.info("Starting display with cached data (fast startup mode)")
@@ -1582,6 +1654,25 @@ class DisplayController:
             logger.info(f"Initial mode set to: {self.current_display_mode} (index: {self.current_mode_index}, total modes: {len(self.available_modes)})")
             
             while True:
+                # Apply plugin enable/disable edits saved via the web UI. The
+                # config-watcher thread only sets the flag; loading/unloading and
+                # rebuilding available_modes happens here on the render thread so
+                # it can't race with rendering. Deferred while on-demand is active
+                # (the flag stays set) so we don't fight its temporary-enable.
+                if self._pending_plugin_reconcile and not self.on_demand_active:
+                    # Only clear the flag on success -- a retryable failure
+                    # (e.g. discovery) leaves it set so the request isn't lost.
+                    if self._reconcile_enabled_plugins():
+                        self._pending_plugin_reconcile = False
+
+                if not self.available_modes:
+                    # Nothing to render yet. Re-check _pending_plugin_reconcile
+                    # every ~1s (rather than a long sleep) so enabling a plugin
+                    # via the web UI is picked up about as promptly as it would
+                    # be once modes exist and the loop is iterating per-frame.
+                    self._sleep_with_plugin_updates(1)
+                    continue
+
                 # Handle on-demand commands before rendering
                 self._poll_on_demand_requests()
                 self._check_on_demand_expiration()
@@ -1624,7 +1715,7 @@ class DisplayController:
                     self._sleep_with_plugin_updates(60)
                     continue
                 
-                logger.info(f"Display active, processing mode: {self.current_display_mode}")
+                logger.debug("Display active, processing mode: %s", self.current_display_mode)
                 
                 # Plugins update on their own schedules - no forced sync updates needed
                 # Each plugin has its own update_interval and background services
@@ -1792,7 +1883,7 @@ class DisplayController:
                         if self.plugin_manager and hasattr(self.plugin_manager, 'health_tracker') and self.plugin_manager.health_tracker:
                             should_skip = self.plugin_manager.health_tracker.should_skip_plugin(plugin_id)
                             if should_skip:
-                                logger.info(f"Skipping plugin {plugin_id} due to circuit breaker (mode: {active_mode})")
+                                logger.info("Skipping plugin %s due to circuit breaker (mode: %s)", plugin_id, active_mode)
                                 display_result = False
                                 # Skip to next mode - let existing logic handle it
                                 manager_to_display = None
@@ -1815,6 +1906,7 @@ class DisplayController:
                     plugin_id = getattr(manager_to_display, 'plugin_id', active_mode)
                     try:
                         logger.debug(f"Calling display() for {active_mode} with force_clear={self.force_change}")
+                        can_display = False
                         if hasattr(manager_to_display, 'display'):
                             # Opt #1: look up (or compute once) whether display() accepts display_mode
                             _cache_key = plugin_id
@@ -1825,14 +1917,64 @@ class DisplayController:
                                 )
                             _accepts_display_mode = self._plugin_accepts_display_mode[_cache_key]
 
-                            # Use PluginExecutor for safe execution with timeout
-                            if self.plugin_manager and hasattr(self.plugin_manager, 'plugin_executor'):
-                                result = self.plugin_manager.plugin_executor.execute_display(
-                                    manager_to_display,
-                                    plugin_id,
-                                    force_clear=self.force_change,
-                                    display_mode=active_mode if _accepts_display_mode else None
-                                )
+                            pm = self.plugin_manager
+                            display_lock = None
+                            can_display = True
+                            if pm and hasattr(pm, 'get_plugin_lock'):
+                                display_lock = pm.get_plugin_lock(plugin_id)
+                                can_display = display_lock.acquire(blocking=False)
+
+                            if not can_display:
+                                # update() in flight on the worker — hold
+                                # the last frame; not a plugin failure
+                                result = True
+                            elif pm and hasattr(pm, 'plugin_executor'):
+                                # PluginExecutor's own thread.join(timeout) can
+                                # return before the real display() call
+                                # finishes (a lingering daemon thread keeps
+                                # running it) -- so the lock is released from
+                                # inside the wrapped call itself, whichever
+                                # thread actually finishes it, rather than
+                                # here when this dispatch merely returns.
+                                release_guard = threading.Lock()
+                                released = {'done': False}
+
+                                def _release_display_lock():
+                                    with release_guard:
+                                        if released['done']:
+                                            return
+                                        released['done'] = True
+                                    if display_lock is not None:
+                                        display_lock.release()
+
+                                if _accepts_display_mode:
+                                    def _display_target(display_mode=None, force_clear=False):
+                                        try:
+                                            return manager_to_display.display(
+                                                display_mode=display_mode, force_clear=force_clear)
+                                        finally:
+                                            _release_display_lock()
+                                else:
+                                    def _display_target(force_clear=False):
+                                        try:
+                                            return manager_to_display.display(force_clear=force_clear)
+                                        finally:
+                                            _release_display_lock()
+
+                                try:
+                                    result = self.plugin_manager.plugin_executor.execute_display(
+                                        types.SimpleNamespace(display=_display_target),
+                                        plugin_id,
+                                        force_clear=self.force_change,
+                                        display_mode=active_mode if _accepts_display_mode else None
+                                    )
+                                except Exception:  # pragma: no cover - defensive;
+                                    # execute_display catches everything
+                                    # internally, but guarantee the lock is
+                                    # never leaked if something unexpected
+                                    # slips through.
+                                    _release_display_lock()
+                                    raise
                                 # execute_display returns bool, convert to expected format
                                 if result:
                                     result = True  # Success
@@ -1840,23 +1982,31 @@ class DisplayController:
                                     result = False  # Failed
                             else:
                                 # Fallback to direct call if executor not available
-                                if _accepts_display_mode:
-                                    result = manager_to_display.display(display_mode=active_mode, force_clear=self.force_change)
-                                else:
-                                    result = manager_to_display.display(force_clear=self.force_change)
+                                try:
+                                    if _accepts_display_mode:
+                                        result = manager_to_display.display(display_mode=active_mode, force_clear=self.force_change)
+                                    else:
+                                        result = manager_to_display.display(force_clear=self.force_change)
+                                finally:
+                                    if display_lock is not None:
+                                        display_lock.release()
                             
                             logger.debug(f"display() returned: {result} (type: {type(result)})")
                             # Check if display() returned a boolean (new behavior)
                             if isinstance(result, bool):
                                 display_result = result
                                 if not display_result:
-                                    logger.info(f"Plugin {plugin_id} display() returned False for mode {active_mode}")
+                                    logger.info("Plugin %s display() returned False for mode %s", plugin_id, active_mode)
                         
-                        # Record success if display completed without exception
-                        if self.plugin_manager and hasattr(self.plugin_manager, 'health_tracker') and self.plugin_manager.health_tracker:
-                            self.plugin_manager.health_tracker.record_success(plugin_id)
-                        
-                        self.force_change = False
+                        # Record success only when display() actually ran this
+                        # frame -- a skipped frame (lock busy) held the last
+                        # frame, not a real success, and must not clear
+                        # force_change or the pending mode-switch clear will
+                        # be lost when display() finally does run.
+                        if can_display:
+                            if self.plugin_manager and hasattr(self.plugin_manager, 'health_tracker') and self.plugin_manager.health_tracker:
+                                self.plugin_manager.health_tracker.record_success(plugin_id)
+                            self.force_change = False
                     except Exception as exc:  # pylint: disable=broad-except
                         logger.exception("Error displaying %s", self.current_display_mode)
                         # Record failure
@@ -2061,10 +2211,23 @@ class DisplayController:
 
                     # For plugins, call display multiple times to allow game rotation
                     if manager_to_display and hasattr(manager_to_display, 'display'):
-                        # Check if plugin needs high FPS (like stock ticker)
-                        # Always enable high-FPS for static-image plugin (for GIF animation support)
+                        # High-FPS decision, in precedence order:
+                        # 1. A plugin that declares needs_high_fps knows best
+                        #    (e.g. static-image sets it False for still PNGs,
+                        #    True for animated GIFs).
+                        # 2. Back-compat: older static-image versions without
+                        #    the attribute keep the historical forced high-FPS
+                        #    (GIF support).
+                        # 3. Otherwise scrolling plugins get high FPS.
                         plugin_id = getattr(manager_to_display, 'plugin_id', None)
-                        if plugin_id == 'static-image':
+                        declared = getattr(manager_to_display, 'needs_high_fps', None)
+                        if declared is not None:
+                            needs_high_fps = bool(declared)
+                            logger.debug(
+                                "[DisplayController] FPS check for %s (plugin=%s) - "
+                                "plugin declares needs_high_fps=%s",
+                                active_mode, plugin_id, needs_high_fps)
+                        elif plugin_id == 'static-image':
                             needs_high_fps = True
                             logger.debug("FPS check - static-image plugin: forcing high-FPS mode for GIF support")
                         else:
@@ -2128,11 +2291,16 @@ class DisplayController:
 
                             while True:
                                 try:
-                                    # Pass display_mode to maintain sticky manager state
-                                    if _accepts_display_mode:
-                                        result = manager_to_display.display(display_mode=active_mode, force_clear=False)
-                                    else:
-                                        result = manager_to_display.display(force_clear=False)
+                                    with self._display_lock_or_skip(plugin_id) as can_display:
+                                        if can_display:
+                                            # Pass display_mode to maintain sticky manager state
+                                            if _accepts_display_mode:
+                                                result = manager_to_display.display(display_mode=active_mode, force_clear=False)
+                                            else:
+                                                result = manager_to_display.display(force_clear=False)
+                                        else:
+                                            # update() in flight — hold the last frame
+                                            result = True
                                     if isinstance(result, bool) and not result:
                                         logger.debug("Display returned False, breaking early")
                                         break
@@ -2192,11 +2360,16 @@ class DisplayController:
                                     break
 
                                 try:
-                                    # Pass display_mode to maintain sticky manager state
-                                    if _accepts_display_mode:
-                                        result = manager_to_display.display(display_mode=active_mode, force_clear=False)
-                                    else:
-                                        result = manager_to_display.display(force_clear=False)
+                                    with self._display_lock_or_skip(plugin_id) as can_display:
+                                        if can_display:
+                                            # Pass display_mode to maintain sticky manager state
+                                            if _accepts_display_mode:
+                                                result = manager_to_display.display(display_mode=active_mode, force_clear=False)
+                                            else:
+                                                result = manager_to_display.display(force_clear=False)
+                                        else:
+                                            # update() in flight — hold the last frame
+                                            result = True
                                     if isinstance(result, bool) and not result:
                                         # For dynamic duration plugins, don't exit on False - keep looping
                                         # until cycle is complete or max duration is reached
@@ -2319,7 +2492,7 @@ class DisplayController:
                         except Exception as e:
                             logger.warning("Error checking live priority for %s: %s", active_mode, e)
                 
-                if should_rotate:
+                if should_rotate and self.available_modes:
                     self.current_mode_index = (self.current_mode_index + 1) % len(self.available_modes)
                     self.current_display_mode = self.available_modes[self.current_mode_index]
                     self.last_mode_change = time.time()
@@ -2343,6 +2516,16 @@ class DisplayController:
             Returns None on any error or if message is expired/invalid.
         """
         try:
+            # Throttle the existence stat to ~1 Hz: this runs on every render
+            # iteration (60+ fps), and the file usually doesn't exist — the
+            # status message's lifetime is measured in seconds anyway.
+            # Both attributes are initialised in __init__.
+            now = time.time()
+            if (now - self._wifi_status_check_ts) < 1.0:
+                return self._wifi_status_last_result
+            self._wifi_status_check_ts = now
+            self._wifi_status_last_result = None
+
             # Check if file exists
             if not self.wifi_status_file or not self.wifi_status_file.exists():
                 return None
@@ -2393,13 +2576,14 @@ class DisplayController:
                     pass
                 return None
             
-            # Message is valid and not expired
-            return {
+            # Message is valid and not expired — cache for the throttle window
+            self._wifi_status_last_result = {
                 'message': message,
                 'timestamp': timestamp,
                 'duration': duration,
                 'expires_at': expires_at
             }
+            return self._wifi_status_last_result
             
         except Exception as e:
             # Catch-all for any unexpected errors - log but don't break the display
@@ -2507,6 +2691,176 @@ class DisplayController:
             self.wifi_status_active = False
             self.wifi_status_expires_at = None
 
+    def _register_loaded_plugin(self, plugin_id: str) -> List[str]:
+        """Register an already-loaded plugin's display modes, config-change
+        subscription and dispatch maps with the controller.
+
+        Shared by startup loading and live enable hot-reload so both paths
+        build identical controller state. Returns the registered modes.
+        """
+        plugin_instance = self.plugin_manager.get_plugin(plugin_id)
+        manifest = self.plugin_manager.plugin_manifests.get(plugin_id, {})
+
+        # Prefer the plugin's dynamic modes attribute (e.g. based on enabled
+        # leagues), else fall back to manifest display_modes, else the id.
+        if plugin_instance is not None and getattr(plugin_instance, 'modes', None):
+            display_modes = list(plugin_instance.modes)
+            logger.debug("Using plugin.modes for %s: %s", plugin_id, display_modes)
+        else:
+            display_modes = manifest.get('display_modes', [plugin_id])
+            logger.debug("Using manifest display_modes for %s: %s", plugin_id, display_modes)
+        if not (isinstance(display_modes, list) and display_modes):
+            display_modes = [plugin_id]
+        self.plugin_display_modes[plugin_id] = list(display_modes)
+
+        # Subscribe to config changes for per-plugin hot-reload. Bind plugin_id
+        # and instance as defaults so each plugin's callback targets its own
+        # instance (avoids late-binding when registering many plugins), and
+        # remember the callback so we can unsubscribe on disable.
+        if hasattr(self, 'config_service') and hasattr(plugin_instance, 'on_config_change'):
+            def config_change_callback(old_config: Dict[str, Any], new_config: Dict[str, Any],
+                                       _pid: str = plugin_id, _plugin: Any = plugin_instance) -> None:
+                """Callback for plugin config changes."""
+                try:
+                    _plugin.on_config_change(new_config)
+                    logger.debug("Plugin %s notified of config change", _pid)
+                except Exception as e:
+                    logger.error("Error in plugin %s config change handler: %s", _pid, e, exc_info=True)
+
+            self.config_service.subscribe(config_change_callback, plugin_id=plugin_id)
+            self._plugin_config_callbacks[plugin_id] = config_change_callback
+            logger.debug("Subscribed plugin %s to config changes", plugin_id)
+
+        # Add modes to the dispatch maps.
+        for mode in display_modes:
+            if mode not in self.available_modes:
+                self.available_modes.append(mode)
+            self.plugin_modes[mode] = plugin_instance
+            self.mode_to_plugin_id[mode] = plugin_id
+            logger.debug("  Added mode: %s", mode)
+        # Invalidate signature cache so the new instance is re-inspected.
+        self._plugin_accepts_display_mode.pop(plugin_id, None)
+        return display_modes
+
+    def _unregister_plugin(self, plugin_id: str) -> None:
+        """Remove a plugin's modes, config subscription and instance, then
+        unload it. Used by live disable hot-reload."""
+        modes = self.plugin_display_modes.pop(plugin_id, [])
+        for mode in modes:
+            if mode in self.available_modes:
+                self.available_modes.remove(mode)
+            self.plugin_modes.pop(mode, None)
+            self.mode_to_plugin_id.pop(mode, None)
+
+        # Unsubscribe the plugin's config-change callback. Pop only on a
+        # successful unsubscribe -- if it raises, keep our reference so a
+        # later retry (or at least cleanup) still has the real callback
+        # instead of a lost one.
+        callback = self._plugin_config_callbacks.get(plugin_id)
+        if callback is not None and hasattr(self, 'config_service'):
+            try:
+                self.config_service.unsubscribe(callback, plugin_id=plugin_id)
+            except Exception as e:
+                logger.debug("Error unsubscribing plugin %s from config changes: %s", plugin_id, e)
+            else:
+                self._plugin_config_callbacks.pop(plugin_id, None)
+        else:
+            self._plugin_config_callbacks.pop(plugin_id, None)
+
+        self._plugin_accepts_display_mode.pop(plugin_id, None)
+
+        # Tear down the instance (cleanup + on_disable + module unload).
+        try:
+            self.plugin_manager.unload_plugin(plugin_id)
+        except Exception as e:
+            logger.error("Error unloading plugin %s: %s", plugin_id, e, exc_info=True)
+
+        logger.info("Disabled plugin %s live (removed modes: %s)", plugin_id, modes)
+
+    def _enabled_set_changed(self, old_config: Dict[str, Any], new_config: Dict[str, Any]) -> bool:
+        """True if any top-level section's ``enabled`` flag differs between two
+        configs. A cheap watcher-thread check that gates the full reconcile.
+        Non-plugin sections (e.g. schedule) may match too; the reconcile
+        no-ops for anything that isn't a discovered plugin."""
+        def enabled_map(cfg: Dict[str, Any]) -> Dict[str, bool]:
+            return {
+                key: bool(value.get('enabled', False))
+                for key, value in cfg.items()
+                if isinstance(value, dict)
+            }
+        return enabled_map(old_config) != enabled_map(new_config)
+
+    def _reconcile_enabled_plugins(self) -> bool:
+        """Load/unload plugins so the running set matches the enabled set in
+        config. Runs on the main display thread (never the config-watcher
+        thread) so mutating available_modes is race-free against rendering.
+
+        Returns True if reconciliation completed (including a no-op), or
+        False on a retryable failure -- the caller keeps the pending-reconcile
+        flag set in that case so the request isn't silently dropped."""
+        if self.plugin_manager is None:
+            return True
+        try:
+            config = self.config_service.get_config()
+        except Exception as e:
+            logger.warning("Plugin reconcile: falling back to cached config: %s", e)
+            config = self.config
+        try:
+            discovered = set(self.plugin_manager.discover_plugins())
+        except Exception as e:
+            logger.error("Plugin reconcile: discovery failed: %s", e, exc_info=True)
+            return False
+
+        for p in discovered:
+            if p in config and not isinstance(config.get(p), dict):
+                logger.warning(
+                    "Plugin reconcile: config for %s is a %s, not a dict; treating as disabled",
+                    p, type(config.get(p)).__name__
+                )
+
+        desired = {
+            p for p in discovered
+            if isinstance(config.get(p), dict) and config.get(p, {}).get('enabled', False)
+        }
+        current = set(self.plugin_display_modes.keys())
+        to_add = desired - current
+        to_remove = current - desired
+        if not to_add and not to_remove:
+            return True
+
+        previous_mode = self.current_display_mode
+
+        for plugin_id in to_remove:
+            self._unregister_plugin(plugin_id)
+
+        for plugin_id in to_add:
+            try:
+                if self.plugin_manager.load_plugin(plugin_id):
+                    modes = self._register_loaded_plugin(plugin_id)
+                    logger.info("Enabled plugin %s live (modes: %s)", plugin_id, modes)
+                else:
+                    logger.warning("Plugin reconcile: failed to load %s", plugin_id)
+            except Exception as e:
+                logger.error("Plugin reconcile: error enabling %s: %s", plugin_id, e, exc_info=True)
+
+        self._resync_mode_index_after_change(previous_mode)
+        logger.info("Plugin reconcile complete: +%s -%s (%d modes)",
+                    sorted(to_add), sorted(to_remove), len(self.available_modes))
+        return True
+
+    def _resync_mode_index_after_change(self, previous_mode: Optional[str]) -> None:
+        """Clamp rotation state after available_modes changed. Stays on the
+        previous mode if it survived, otherwise restarts cleanly within range."""
+        if not self.available_modes:
+            self.current_mode_index = 0
+            self.current_display_mode = None
+            return
+        if previous_mode in self.available_modes:
+            self.current_mode_index = self.available_modes.index(previous_mode)
+        else:
+            self.current_mode_index %= len(self.available_modes)
+            self.current_display_mode = self.available_modes[self.current_mode_index]
+
     def _refresh_config_cache(self, new_config: Dict[str, Any]) -> None:
         """Refresh all config-derived caches when a hot-reload fires.
 
@@ -2533,6 +2887,14 @@ class DisplayController:
 
     def cleanup(self):
         """Clean up resources."""
+        # Stop the async update worker first so no in-flight update() call
+        # is still touching display/cache-backed resources while they're
+        # torn down below.
+        if self.plugin_manager and hasattr(self.plugin_manager, 'stop_update_worker'):
+            try:
+                self.plugin_manager.stop_update_worker()
+            except Exception as e:
+                logger.warning("Error stopping plugin update worker: %s", e)
         # Shutdown config service if it exists
         if hasattr(self, 'config_service'):
             try:

src/display_manager.py

@@ -31,13 +31,25 @@ if os.getenv("EMULATOR", "false") == "true":
 else:
     from rgbmatrix import RGBMatrix, RGBMatrixOptions
 from contextlib import contextmanager
+from pathlib import Path
 from PIL import Image, ImageDraw, ImageFont
+import threading
 import time
-from typing import Dict, Any, List, Optional
+from collections import OrderedDict
+from typing import Dict, Any, List, Optional, Tuple
 import logging
 import math
+import zlib
 import freetype
 
+from src.common import snapshot_policy
+from src.common.permission_utils import (
+    ensure_directory_permissions,
+    ensure_file_permissions,
+    get_assets_dir_mode,
+    get_assets_file_mode,
+)
+
 # Get logger without configuring
 logger = logging.getLogger(__name__)
 logger.setLevel(logging.INFO)  # Set to INFO level
@@ -180,14 +192,45 @@ class DisplayManager:
         # the logical image is blitted to the matrix unchanged.
         self._double_sided = None  # dict {copies, axis, logical_width, logical_height} or None
         self._physical_image = None  # full-chain buffer reused each frame when tiling
-        # Text-width measurement cache: (text, id(font)) -> pixel_width
+        # Text-width measurement cache: (text, id(font)) -> (width, font_ref)
         # Avoids re-measuring the same string+font on every display() call.
+        # LRU-bounded: keys embed the TEXT, so changing strings (a clock, a
+        # live score) would otherwise grow it forever on a 24/7 service.
+        # Entries hold a strong reference to the font so its id() can't be
+        # recycled by a different font object — an id-keyed cache without
+        # the reference can return the WRONG width after garbage collection.
         # Cleared on _load_fonts() so stale entries don't survive a font reload.
-        self._text_width_cache: Dict[tuple, int] = {}
-        # Snapshot settings for web preview integration (service writes, web reads)
+        self._text_width_cache: "OrderedDict[tuple, Tuple[int, Any]]" = OrderedDict()
+        self._TEXT_WIDTH_CACHE_MAX = 1024
+        # Snapshot mirror for web preview + health check (service writes, web
+        # reads). Cadence/skip decisions live in src/common/snapshot_policy.py:
+        # full rate only while the web SSE broadcaster keeps the viewer marker
+        # fresh; unchanged frames are never re-encoded, only mtime-touched.
         self._snapshot_path = "/tmp/led_matrix_preview.png"  # nosec B108 - fixed path intentional; web UI reads same path
-        self._snapshot_min_interval_sec = 0.2  # max ~5 fps
+        self._viewer_marker_path = "/tmp/led_matrix_preview_viewer"  # nosec B108 - touched by web SSE broadcaster
         self._last_snapshot_ts = 0.0
+        self._last_snapshot_touch_ts = 0.0
+        self._last_snapshot_digest: Optional[int] = None
+        self._snapshot_dir_prepared = False
+        self._viewer_check_ts = 0.0
+        self._viewer_fresh = False
+        self._viewer_was_fresh = False
+        # Snapshot failures are logged as warnings, rate-limited so a
+        # persistent failure (e.g. an unwritable file) can't spam the log —
+        # but is never silent: the snapshot's mtime doubles as the web UI's
+        # hardware-liveness signal, so a quiet failure makes health checks lie.
+        self._snapshot_fail_log_ts = 0.0
+        # Dirty tracking: (image digest, brightness) of the last frame pushed
+        # to the panel; update_display() skips identical pushes. Kill switch:
+        # display.dirty_tracking: false.
+        self._dirty_tracking_enabled = bool(
+            self.config.get('display', {}).get('dirty_tracking', True))
+        self._last_pushed_digest = None
+        # Serializes update_display(): plugins can call it directly from
+        # background threads (see docstring on update_display), not just the
+        # render loop. RLock in case a caller within the critical section
+        # ever re-enters (e.g. via a nested draw callback).
+        self._update_lock = threading.RLock()
         
         # Scrolling state tracking for graceful updates
         self._scrolling_state = {
@@ -418,6 +461,10 @@ class DisplayManager:
         try:
             # RGBMatrix accepts brightness as a property
             self.matrix.brightness = brightness
+            # Brightness applies on the next swap — force a re-push even if
+            # the image itself is unchanged (belt-and-braces: brightness is
+            # also part of the dirty-tracking digest when readable).
+            self._last_pushed_digest = None
             logger.info(f"[BRIGHTNESS] Display brightness set to {brightness}%")
             return True
         except AttributeError as e:
@@ -509,33 +556,70 @@ class DisplayManager:
         return phys
 
     def update_display(self):
-        """Update the display using double buffering with proper sync."""
+        """Update the display using double buffering with proper sync.
+
+        Skips the panel push entirely when the frame is byte-identical to
+        the last pushed one (same image digest AND same brightness) — static
+        content re-rendered every second, and 125 fps loops between actual
+        scroll steps, otherwise re-walk the full framebuffer for nothing.
+        The panel keeps refreshing the current frame from its own thread,
+        so skipping a swap never blanks or freezes the hardware.
+
+        Correctness hinges on invalidation: clear() resets the digest (it
+        writes to the matrix directly), and brightness is PART of the digest
+        so a dim-schedule change is never skipped. Disable via config
+        ``display.dirty_tracking: false`` if a redraw issue is ever suspected.
+
+        Serialized via ``_update_lock``: plugins can call this directly from
+        background threads (e.g. sports base classes push an immediate
+        "live" refresh from inside update()), so without a lock two callers
+        could both pass the digest check before either writes it back,
+        double-pushing a frame, or interleave the offscreen/current canvas
+        swap below. The lock is scoped to this method, so callers never
+        need to know about it.
+        """
         try:
-            if self.matrix is None:
-                # Fallback mode - no actual hardware to update
-                logger.debug("Update display called in fallback mode (no hardware)")
-                # Still write a snapshot so the web UI can preview
+            with self._update_lock:
+                if self.matrix is None:
+                    # Fallback mode - no actual hardware to update
+                    logger.debug("Update display called in fallback mode (no hardware)")
+                    # Still write a snapshot so the web UI can preview
+                    self._write_snapshot_if_due()
+                    return
+
+                if self._capture_mode_active:
+                    return  # Skip hardware write — content is being captured off-screen
+
+                digest = None
+                if self._dirty_tracking_enabled:
+                    try:
+                        brightness = getattr(self.matrix, 'brightness', None)
+                    except AttributeError:
+                        brightness = None
+                    digest = (zlib.adler32(self.image.tobytes()), brightness)
+                    if digest == self._last_pushed_digest:
+                        # Nothing changed since the last push — the panel is
+                        # already showing exactly this frame.
+                        self._write_snapshot_if_due()
+                        return
+
+                # Copy the current image to the offscreen canvas. In double-sided
+                # mode the logical screen is first tiled across the full chain.
+                if self._double_sided is not None:
+                    self.offscreen_canvas.SetImage(self._composite_double_sided())
+                else:
+                    self.offscreen_canvas.SetImage(self.image)
+
+                # Swap buffers immediately
+                self.matrix.SwapOnVSync(self.offscreen_canvas)
+
+                # Swap our canvas references
+                self.offscreen_canvas, self.current_canvas = self.current_canvas, self.offscreen_canvas
+
+                self._last_pushed_digest = digest
+
+                # Write a snapshot for the web preview (throttled)
                 self._write_snapshot_if_due()
-                return
-
-            if self._capture_mode_active:
-                return  # Skip hardware write — content is being captured off-screen
-
-            # Copy the current image to the offscreen canvas. In double-sided
-            # mode the logical screen is first tiled across the full chain.
-            if self._double_sided is not None:
-                self.offscreen_canvas.SetImage(self._composite_double_sided())
-            else:
-                self.offscreen_canvas.SetImage(self.image)
-
-            # Swap buffers immediately
-            self.matrix.SwapOnVSync(self.offscreen_canvas)
-            
-            # Swap our canvas references
-            self.offscreen_canvas, self.current_canvas = self.current_canvas, self.offscreen_canvas
-
-            # Write a snapshot for the web preview (throttled)
-            self._write_snapshot_if_due()
         except Exception as e:
             logger.error(f"Error updating display: {e}")
 
@@ -569,6 +653,9 @@ class DisplayManager:
                 # Clear both canvases and the underlying matrix to ensure no artifacts.
                 # Failures are non-fatal — the image buffer is already black above, so
                 # the next update_display() call will push clean content regardless.
+                # The matrix content no longer matches the last pushed digest,
+                # so dirty tracking must not skip the next push.
+                self._last_pushed_digest = None
                 try:
                     self.offscreen_canvas.Clear()
                 except (RuntimeError, OSError) as e:
@@ -699,12 +786,15 @@ class DisplayManager:
 
         Results are cached by (text, font identity) so plugins that measure
         the same string every frame (e.g. to centre a score) pay only one
-        measurement per unique (text, font) pair.
+        measurement per unique (text, font) pair. The entry keeps the font
+        alive so its id() can't be recycled, and the cache is LRU-bounded so
+        ever-changing text (clocks, tickers) can't grow it without limit.
         """
         cache_key = (text, id(font))
         cached = self._text_width_cache.get(cache_key)
         if cached is not None:
-            return cached
+            self._text_width_cache.move_to_end(cache_key)
+            return cached[0]
 
         try:
             if isinstance(font, freetype.Face):
@@ -719,7 +809,9 @@ class DisplayManager:
             logger.error("Error getting text width: %s", e)
             return 0
 
-        self._text_width_cache[cache_key] = width
+        self._text_width_cache[cache_key] = (width, font)
+        while len(self._text_width_cache) > self._TEXT_WIDTH_CACHE_MAX:
+            self._text_width_cache.popitem(last=False)
         return width
 
     def get_font_height(self, font):
@@ -1128,27 +1220,56 @@ class DisplayManager:
             'deferred_update_ttl': self._scrolling_state['deferred_update_ttl']
         }
 
+    def _viewer_is_fresh(self, now: float) -> bool:
+        """True when a browser preview is watching (marker file touched by
+        the web SSE broadcaster). The marker is stat'd at most once per
+        second — at 125 fps loops a per-call stat would be pure overhead."""
+        if (now - self._viewer_check_ts) >= 1.0:
+            self._viewer_check_ts = now
+            try:
+                marker_age = now - os.stat(self._viewer_marker_path).st_mtime
+                self._viewer_fresh = marker_age < snapshot_policy.VIEWER_MARKER_FRESH_SEC
+            except OSError:
+                self._viewer_fresh = False
+        return self._viewer_fresh
+
     def _write_snapshot_if_due(self) -> None:
-        """Write the current image to a PNG snapshot file at a limited frequency."""
+        """Mirror the current frame to the preview snapshot when the policy
+        says it's worth it — see src/common/snapshot_policy.py. Unchanged
+        frames are never re-encoded; without viewers the cadence drops to
+        the idle keepalive."""
         try:
             now = time.time()
-            if (now - self._last_snapshot_ts) < self._snapshot_min_interval_sec:
+            viewer_fresh = self._viewer_is_fresh(now)
+            if viewer_fresh and not self._viewer_was_fresh:
+                # A preview just opened: let the next changed frame through
+                # immediately instead of waiting out the idle interval.
+                self._last_snapshot_ts = 0.0
+            self._viewer_was_fresh = viewer_fresh
+
+            digest = zlib.adler32(self.image.tobytes())
+            action = snapshot_policy.decide(
+                now, self._last_snapshot_ts, self._last_snapshot_touch_ts,
+                viewer_fresh, digest != self._last_snapshot_digest)
+            if action is snapshot_policy.SnapshotAction.SKIP:
                 return
-            # Ensure directory exists with proper permissions
-            from pathlib import Path
-            from src.common.permission_utils import (
-                ensure_directory_permissions,
-                ensure_file_permissions,
-                get_assets_dir_mode,
-                get_assets_file_mode
-            )
+            if action is snapshot_policy.SnapshotAction.TOUCH:
+                # mtime bump only: keeps the health check (snapshot age)
+                # green without paying for a PNG encode of an unchanged frame
+                os.utime(self._snapshot_path, None)
+                self._last_snapshot_touch_ts = now
+                return
+
+            # WRITE: ensure directory permissions once, not per frame
             snapshot_path_obj = Path(self._snapshot_path)
-            # Only ensure permissions on non-system directories
-            # Never modify /tmp permissions - it has special system permissions (1777)
-            # that must not be changed or it breaks apt and other system tools
-            parent_dir = snapshot_path_obj.parent
-            if parent_dir and str(parent_dir) != '/tmp':  # nosec B108 - guard to skip /tmp for permission ops
-                ensure_directory_permissions(parent_dir, get_assets_dir_mode())
+            if not self._snapshot_dir_prepared:
+                # Never modify /tmp permissions - it has special system
+                # permissions (1777) that must not be changed or it breaks
+                # apt and other system tools
+                parent_dir = snapshot_path_obj.parent
+                if parent_dir and str(parent_dir) != '/tmp':  # nosec B108 - guard to skip /tmp for permission ops
+                    ensure_directory_permissions(parent_dir, get_assets_dir_mode())
+                self._snapshot_dir_prepared = True
             # Write atomically: temp then replace
             tmp_path = f"{self._snapshot_path}.tmp"
             self.image.save(tmp_path, format='PNG')
@@ -1163,6 +1284,18 @@ class DisplayManager:
             except Exception:
                 pass
             self._last_snapshot_ts = now
+            self._last_snapshot_touch_ts = now
+            self._last_snapshot_digest = digest
         except Exception as e:
-            # Snapshot failures should never break display; log at debug to avoid noise
-            logger.debug(f"Snapshot write skipped: {e}")
+            # Snapshot failures must never break display — but they must not
+            # be silent either: the snapshot's mtime is the web UI's display
+            # mirror AND its hardware-liveness proxy, so a quietly failing
+            # write freezes the mirror and makes health checks lie (seen in
+            # the field: a stale root-owned /tmp file froze it for a day).
+            # Warn at most once per 5 minutes to avoid log spam.
+            if (now - self._snapshot_fail_log_ts) > 300:
+                self._snapshot_fail_log_ts = now
+                logger.warning("Snapshot write failing (web preview/health "
+                               "mirror is stale): %s", e)
+            else:
+                logger.debug(f"Snapshot write skipped: {e}")

src/font_manager.py

@@ -35,6 +35,7 @@ import urllib.request
 import zipfile
 import tempfile
 import time
+from collections import OrderedDict
 from pathlib import Path
 from PIL import ImageFont
 from typing import Dict, Tuple, Optional, Union, Any, List
@@ -58,7 +59,13 @@ class FontManager:
         # Font discovery and catalog
         self.font_catalog: Dict[str, str] = {}  # family_name -> file_path
         self.font_cache: Dict[str, Union[ImageFont.FreeTypeFont, freetype.Face]] = {}  # (family, size) -> font
-        self.metrics_cache: Dict[str, Tuple[int, int, int]] = {}  # (text, font_id) -> (width, height, baseline)
+        # (text, id(font)) -> ((width, height, baseline), font_ref).
+        # LRU-bounded — keys embed the measured TEXT, so changing strings
+        # (clocks, live scores) would otherwise grow it forever. Entries
+        # keep the font alive so its id() can't be recycled by a different
+        # font object (which would silently return wrong metrics).
+        self.metrics_cache: "OrderedDict[Any, Tuple[Tuple[int, int, int], Any]]" = OrderedDict()
+        self._METRICS_CACHE_MAX = 1024
 
         # Plugin font management
         self.plugin_fonts: Dict[str, Dict[str, Any]] = {}  # plugin_id -> font_manifest
@@ -103,6 +110,10 @@ class FontManager:
         # Font overrides storage (for manual overrides)
         self.font_overrides_file = "config/font_overrides.json"
         self.font_overrides: Dict[str, Dict[str, Any]] = {}
+
+        # Bumped whenever cached font objects are invalidated, so holders of
+        # derived caches (e.g. adaptive-layout fit results) know to rebuild.
+        self.cache_generation = 0
         
         self._initialize_fonts()
     
@@ -112,6 +123,7 @@ class FontManager:
         self.fonts_config = new_config.get("fonts", {})
         self.font_cache.clear()  # Clear cache to force reload
         self.metrics_cache.clear()  # Clear metrics cache
+        self.cache_generation += 1
         self._initialize_fonts()
         logger.info("FontManager configuration reloaded successfully")
 
@@ -482,6 +494,14 @@ class FontManager:
     def _load_bdf_font(self, font_path: str, size_px: int) -> freetype.Face:
         """Load a BDF font using FreeType."""
         try:
+            native_size = self._read_bdf_native_size(font_path)
+            if native_size is not None and native_size != size_px:
+                # BDF is a fixed-strike bitmap format: FreeType renders the
+                # native size no matter what set_char_size asks for.
+                logger.debug(
+                    "BDF font %s requested at %spx but renders at its native "
+                    "%spx", font_path, size_px, native_size
+                )
             face = freetype.Face(font_path)
             # Set character size (width, height) in 1/64th of points
             face.set_char_size(size_px * 64, size_px * 64, 72, 72)
@@ -490,6 +510,41 @@ class FontManager:
             logger.error(f"Error loading BDF font {font_path}: {e}")
             raise
 
+    def get_native_bdf_size(self, family: str) -> Optional[int]:
+        """The one true pixel size of a BDF family in the catalog, or None
+        for scalable (TTF) families / unknown families."""
+        font_path = self.font_catalog.get(family)
+        if not font_path or not font_path.endswith('.bdf'):
+            return None
+        return self._read_bdf_native_size(font_path)
+
+    @staticmethod
+    def _read_bdf_native_size(bdf_path: str) -> Optional[int]:
+        """Read a BDF file's own header to find its one true pixel size.
+        Prefers the PIXEL_SIZE property, which states the real pixel height
+        directly; falls back to the SIZE line's point-size only if PIXEL_SIZE
+        is absent, since point-size only equals pixel height at exactly
+        100dpi — several bundled fonts (e.g. 6x13.bdf, 5x8.bdf) are defined
+        at 75dpi, where the two values genuinely differ."""
+        size_line_value = None
+        try:
+            with open(bdf_path, "r", encoding="ascii", errors="ignore") as f:
+                for line in f:
+                    if line.startswith("PIXEL_SIZE"):
+                        parts = line.split()
+                        if len(parts) >= 2:
+                            return int(float(parts[1]))
+                    elif line.startswith("SIZE") and size_line_value is None:
+                        # Format: "SIZE <point_size> <xres> <yres>"
+                        parts = line.split()
+                        if len(parts) >= 2:
+                            size_line_value = int(float(parts[1]))
+                    elif line.startswith("STARTCHAR"):
+                        break
+        except (OSError, ValueError):
+            return None
+        return size_line_value
+
     def _get_fallback_font(self) -> ImageFont.ImageFont:
         """Get a fallback font when loading fails."""
         return ImageFont.load_default()
@@ -507,10 +562,14 @@ class FontManager:
         Returns:
             Tuple of (width, height, baseline_offset)
         """
-        cache_key = f"{hash(text)}_{id(font)}"
+        # Key on the text itself (hash(text) could collide) + font identity;
+        # the entry below keeps the font referenced so the id stays valid.
+        cache_key = (text, id(font))
 
-        if cache_key in self.metrics_cache:
-            return self.metrics_cache[cache_key]
+        cached = self.metrics_cache.get(cache_key)
+        if cached is not None:
+            self.metrics_cache.move_to_end(cache_key)
+            return cached[0]
 
         try:
             if isinstance(font, freetype.Face):
@@ -547,7 +606,9 @@ class FontManager:
             baseline = 10
 
         result = (width, height, baseline)
-        self.metrics_cache[cache_key] = result
+        self.metrics_cache[cache_key] = (result, font)
+        while len(self.metrics_cache) > self._METRICS_CACHE_MAX:
+            self.metrics_cache.popitem(last=False)
         return result
 
     def get_font_height(self, font: Union[ImageFont.FreeTypeFont, freetype.Face]) -> int:

src/image_utils.py

@@ -1,3 +1,9 @@
+"""Deprecated: use src/adaptive_images.py (fit_image) instead.
+
+This module predates the adaptive image system and has no known callers.
+It is kept only so any out-of-tree code importing it keeps working.
+"""
+
 import logging
 from PIL import Image
 

src/plugin_system/base_plugin.py

@@ -15,6 +15,19 @@ import logging
 from src.logging_config import get_logger
 
 
+_shared_fallback_font_manager: Optional[Any] = None
+
+
+def _fallback_font_manager() -> Any:
+    """Shared FontManager for environments (unit tests, mocks) where the
+    plugin manager doesn't carry one. Scans assets/fonts like the real one."""
+    global _shared_fallback_font_manager
+    if _shared_fallback_font_manager is None:
+        from src.font_manager import FontManager
+        _shared_fallback_font_manager = FontManager({})
+    return _shared_fallback_font_manager
+
+
 class VegasDisplayMode(Enum):
     """
     Display mode for Vegas scroll integration.
@@ -130,6 +143,133 @@ class BasePlugin(ABC):
         """
         raise NotImplementedError("Plugins must implement display()")
 
+    # -------------------------------------------------------------------------
+    # Adaptive layout support (opt-in)
+    # -------------------------------------------------------------------------
+    @property
+    def layout(self) -> Any:
+        """
+        LayoutContext for the current logical display size.
+
+        Lazily built and rebuilt automatically when the display size changes
+        (e.g. Vegas segment widths, double-sided logical screens). Provides
+        Region carving (self.layout.bounds), breakpoint tiers, a geometry
+        scale factor vs. the manifest's display.design_size, and fit-text
+        queries against font ladders. See src/adaptive_layout.py.
+
+        Example:
+            rows = self.layout.bounds.inset(1).split_v(3, 1, gap=1)
+            self.draw_fit(big_text, rows[0], ladder=LADDER_ARCADE)
+            self.draw_fit(small_text, rows[1])
+        """
+        from src.adaptive_layout import LayoutContext
+
+        width = getattr(self.display_manager, "width", None)
+        height = getattr(self.display_manager, "height", None)
+        if not width or not height:
+            matrix = getattr(self.display_manager, "matrix", None)
+            width = getattr(matrix, "width", 128)
+            height = getattr(matrix, "height", 32)
+
+        font_manager = self._get_font_manager()
+        generation = getattr(font_manager, "cache_generation", 0)
+        cached = getattr(self, "_layout_context", None)
+        if (cached is not None
+                and (cached.width, cached.height) == (width, height)
+                and getattr(self, "_layout_font_generation", None) == generation):
+            return cached
+
+        context = LayoutContext(
+            width, height, font_manager,
+            design_size=self._get_design_size(),
+        )
+        self._layout_context = context
+        self._layout_font_generation = generation
+        return context
+
+    def draw_fit(self, text: str, box: Any,
+                 color: tuple = (255, 255, 255),
+                 ladder: Optional[Any] = None,
+                 align: str = "center", valign: str = "center") -> Any:
+        """
+        Fit text to a Region with the largest crisp font that fits, then draw
+        it aligned within that region via the display manager.
+
+        Args:
+            text: Text to display (ellipsized if even the smallest rung is too wide)
+            box: Region (or (w, h) tuple anchored at 0,0) to fit and align within
+            color: RGB color tuple
+            ladder: FontLadder to walk (default LADDER_GRID; use LADDER_ARCADE
+                    for headline text like clocks and scores)
+            align/valign: alignment of the text ink within the box
+
+        Returns:
+            FitResult (font, family, size_px, text, ink metrics, fits flag)
+        """
+        from src.adaptive_layout import LADDER_DEFAULT, draw_fitted_text
+
+        fit = self.layout.fit_text(text, box, ladder=ladder or LADDER_DEFAULT)
+        draw_fitted_text(self.display_manager, fit, box,
+                         color=color, align=align, valign=valign)
+        return fit
+
+    def draw_image(self, img: Any, box: Any, *,
+                   mode: str = "contain", align: str = "center",
+                   valign: str = "center", crop_to_ink: bool = False,
+                   anchor: str = "center", resample: Optional[Any] = None,
+                   cache_key: Optional[Any] = None,
+                   offset: tuple = (0, 0)) -> Any:
+        """
+        Fit an image into a Region and paste it aligned within that region
+        onto the display canvas — the image counterpart to draw_fit().
+
+        Args:
+            img: Source PIL image (logos, art, icons)
+            box: Region (or (w, h) tuple) to fit and align within
+            mode: "contain" (letterbox), "cover" (crop-to-fill),
+                  "fill_height" (logo-style), "stretch"
+            crop_to_ink: Trim transparent padding before fitting
+            anchor: "center" or "top" for cover crops
+            resample: PIL filter; default LANCZOS. Use RESAMPLE_NEAREST
+                  (from src.adaptive_images) for pixel art/flags
+            cache_key: Stable identity (e.g. "logo:KC") for cross-reload
+                  caching; defaults to the image object's identity
+            offset: Final (dx, dy) translation — the hook for user
+                  x/y-offset customization
+
+        Returns:
+            ImageFitResult (processed image + dimensions + scale)
+        """
+        from src.adaptive_images import draw_fitted_image
+
+        ifit = self.layout.fit_image(img, box, mode=mode,
+                                     crop_to_ink=crop_to_ink, anchor=anchor,
+                                     resample=resample, cache_key=cache_key)
+        draw_fitted_image(self.display_manager, ifit, box,
+                          align=align, valign=valign, offset=offset)
+        return ifit
+
+    def _get_font_manager(self) -> Any:
+        """The shared FontManager, or a module-level fallback when running
+        under mocks/harnesses that don't provide one."""
+        font_manager = getattr(self.plugin_manager, "font_manager", None)
+        if font_manager is not None and hasattr(font_manager, "get_font"):
+            return font_manager
+        return _fallback_font_manager()
+
+    def _get_design_size(self) -> tuple:
+        """Panel size this plugin's layout was authored against, from the
+        manifest's optional display.design_size (defaults to 128x32)."""
+        from src.adaptive_layout import DEFAULT_DESIGN_SIZE
+
+        if self.plugin_manager and hasattr(self.plugin_manager, "plugin_manifests"):
+            manifest = self.plugin_manager.plugin_manifests.get(self.plugin_id, {})
+            declared = manifest.get("display", {}).get("design_size", {})
+            width, height = declared.get("width"), declared.get("height")
+            if width and height:
+                return (int(width), int(height))
+        return DEFAULT_DESIGN_SIZE
+
     def get_display_duration(self) -> float:
         """
         Get the display duration for this plugin instance.

src/plugin_system/plugin_health.py

@@ -52,11 +52,18 @@ class PluginHealthTracker:
         """Get cache key for plugin health data."""
         return f"plugin_health:{plugin_id}"
     
-    def _load_health_state(self, plugin_id: str) -> Dict[str, Any]:
-        """Load health state from cache or return defaults."""
+    def _load_health_state(self, plugin_id: str, force_reload: bool = False) -> Dict[str, Any]:
+        """Load health state from cache or return defaults.
+
+        ``force_reload=True`` bypasses the cache manager's in-memory tier so a
+        read-only consumer (e.g. the web process) observes the writer process's
+        latest persisted state instead of a stale first snapshot.
+        """
         cache_key = self._get_health_key(plugin_id)
-        cached = self.cache_manager.get(cache_key, max_age=None)
-        
+        cached = self.cache_manager.get(
+            cache_key, max_age=None, memory_ttl=0 if force_reload else None
+        )
+
         if cached:
             return cached
         
@@ -79,10 +86,17 @@ class PluginHealthTracker:
         self.cache_manager.set(cache_key, state)  # Persist indefinitely
         self._health_state[plugin_id] = state
     
-    def get_health_state(self, plugin_id: str) -> Dict[str, Any]:
-        """Get current health state for a plugin."""
-        if plugin_id not in self._health_state:
-            self._health_state[plugin_id] = self._load_health_state(plugin_id)
+    def get_health_state(self, plugin_id: str, force_reload: bool = False) -> Dict[str, Any]:
+        """Get current health state for a plugin.
+
+        ``force_reload=True`` re-reads the persisted state from the cache,
+        bypassing the in-memory copy — needed by cross-process readers that
+        would otherwise be pinned to the first snapshot they loaded.
+        """
+        if force_reload or plugin_id not in self._health_state:
+            self._health_state[plugin_id] = self._load_health_state(
+                plugin_id, force_reload=force_reload
+            )
         return self._health_state[plugin_id]
     
     def record_success(self, plugin_id: str) -> None:
@@ -139,6 +153,28 @@ class PluginHealthTracker:
         
         self._save_health_state(plugin_id, state)
     
+    def set_degraded(self, plugin_id: str, reason: Optional[str]) -> None:
+        """Flag (or clear) a plugin as degraded without touching the circuit breaker.
+
+        Used for non-fatal issues — e.g. a config that no longer satisfies the
+        plugin's schema — that should be surfaced to the user but must NOT cause
+        the plugin to be skipped or counted as a runtime failure. Passing
+        ``reason=None`` clears the flag. The write is skipped when nothing
+        actually changes, so calling this on every load is cheap.
+
+        Args:
+            plugin_id: Plugin identifier
+            reason: Human-readable reason string, or None to clear the flag
+        """
+        state = self.get_health_state(plugin_id)
+        new_degraded = bool(reason)
+        new_reason = reason if reason else None
+        if state.get('degraded', False) == new_degraded and state.get('degraded_reason') == new_reason:
+            return  # No change — avoid a redundant cache write
+        state['degraded'] = new_degraded
+        state['degraded_reason'] = new_reason
+        self._save_health_state(plugin_id, state)
+
     def should_skip_plugin(self, plugin_id: str) -> bool:
         """
         Check if plugin should be skipped due to circuit breaker.
@@ -181,9 +217,13 @@ class PluginHealthTracker:
         
         return False
     
-    def get_health_summary(self, plugin_id: str) -> Dict[str, Any]:
-        """Get health summary for a plugin."""
-        state = self.get_health_state(plugin_id)
+    def get_health_summary(self, plugin_id: str, force_reload: bool = False) -> Dict[str, Any]:
+        """Get health summary for a plugin.
+
+        ``force_reload=True`` refreshes from the persisted cache first so
+        cross-process readers reflect the writer's latest state.
+        """
+        state = self.get_health_state(plugin_id, force_reload=force_reload)
         
         total_calls = state.get('total_successes', 0) + state.get('total_failures', 0)
         success_rate = 0.0
@@ -201,6 +241,8 @@ class PluginHealthTracker:
             'last_failure_time': state.get('last_failure_time'),
             'last_error': state.get('last_error'),
             'is_healthy': state.get('circuit_state') == CircuitState.CLOSED.value,
+            'degraded': state.get('degraded', False),
+            'degraded_reason': state.get('degraded_reason'),
             'circuit_opened_time': state.get('circuit_opened_time'),
             'half_open_start_time': state.get('half_open_start_time')
         }

src/plugin_system/plugin_loader.py

@@ -5,10 +5,10 @@ Handles plugin module imports, dependency installation, and class instantiation.
 Extracted from PluginManager to improve separation of concerns.
 """
 
-import hashlib
-import json
 import importlib
+import importlib.metadata
 import importlib.util
+import json
 import os
 import sys
 import subprocess
@@ -17,12 +17,101 @@ from pathlib import Path
 from typing import Dict, Any, Optional, Tuple, Type
 import logging
 
+from packaging.requirements import InvalidRequirement, Requirement
+
 from src.exceptions import PluginError
 from src.logging_config import get_logger
-from src.common.permission_utils import (
-    ensure_file_permissions,
-    get_plugin_file_mode
-)
+
+
+def requirements_has_real_deps(requirements_file: str) -> bool:
+    """
+    Check whether a requirements.txt actually specifies anything to install.
+
+    Plugins that ship all their dependencies with LEDMatrix core often keep a
+    requirements.txt where every line is commented out, for documentation
+    purposes only. Running pip against such a file still pays the full
+    subprocess/resolver cost for zero effect, so callers should skip the
+    install step entirely when this returns False.
+    """
+    try:
+        with open(requirements_file, 'r', encoding='utf-8') as fh:
+            for line in fh:
+                line = line.strip()
+                if line and not line.startswith('#'):
+                    return True
+    except OSError:
+        # Let the caller's own file handling report the error.
+        return True
+    return False
+
+
+def requirements_are_satisfied(requirements_file: str) -> bool:
+    """
+    Check whether every real requirement line in requirements.txt is already
+    satisfied by packages installed in the current interpreter.
+
+    This replaces marker-file tracking with a direct fact check, so it's
+    immune to stale/missing/corrupted markers: it looks at what's actually
+    importable right now rather than trusting a hash comparison from a
+    previous run. Anything ambiguous (pip options, unparseable lines,
+    extras, unresolvable versions) conservatively returns False so the
+    caller falls through to running pip — this check only ever saves work,
+    never masks a real install.
+    """
+    try:
+        with open(requirements_file, 'r', encoding='utf-8') as fh:
+            lines = fh.readlines()
+    except OSError:
+        return False
+
+    for raw_line in lines:
+        line = raw_line.strip()
+        if not line or line.startswith('#'):
+            continue
+        if line.startswith('-'):
+            return False  # pip option (-r, --index-url, ...), can't verify
+
+        try:
+            req = Requirement(line)
+        except InvalidRequirement:
+            return False
+
+        if req.extras:
+            return False  # verifying extras' sub-dependencies isn't worth it here
+
+        if req.marker is not None and not req.marker.evaluate():
+            continue  # not applicable on this platform/interpreter
+
+        try:
+            installed_version = importlib.metadata.version(req.name)
+        except importlib.metadata.PackageNotFoundError:
+            return False
+
+        if req.specifier and not req.specifier.contains(installed_version, prereleases=True):
+            return False
+
+    return True
+
+
+def find_trusted_subdir(trusted_dir: str, name: str) -> Optional[str]:
+    """Return `name` if it names an actual subdirectory of trusted_dir, else None.
+
+    Used as a containment check for a directory name derived from untrusted
+    input (a manifest-declared plugin id, an externally-supplied plugin
+    path): the returned value always comes from enumerating trusted_dir
+    itself via os.scandir(), so a caller that builds a path by joining
+    trusted_dir with this return value is joining against a name the
+    filesystem produced under a trusted root -- not the caller's original
+    string, which could otherwise smuggle a traversal sequence through.
+    """
+    try:
+        with os.scandir(trusted_dir) as entries:
+            for entry in entries:
+                if entry.name == name and entry.is_dir():
+                    return entry.name
+    except OSError:
+        pass
+    return None
 
 
 class PluginLoader:
@@ -132,14 +221,14 @@ class PluginLoader:
                 except (json.JSONDecodeError, Exception) as e:
                     self.logger.debug("Skipping %s due to manifest error: %s", item.name, e)
                     continue
-        
+
         return None
-    
+
     def install_dependencies(
         self,
         plugin_dir: Path,
         plugin_id: str,
-        plugins_dir: Optional[Path] = None,
+        plugins_dir: Path,
         timeout: int = 300
     ) -> bool:
         """
@@ -148,7 +237,12 @@ class PluginLoader:
         Args:
             plugin_dir: Plugin directory path
             plugin_id: Plugin identifier
-            plugins_dir: Trusted base plugins directory for path containment check
+            plugins_dir: Trusted base plugins directory for path containment check.
+                Required (not optional) so every caller reconstructs the plugin
+                path through the sanitiser below rather than trusting plugin_dir
+                directly -- CodeQL's path-injection query (and a malicious
+                manifest/plugin_id in practice) can't tell a legitimate
+                plugin_dir from one crafted to traverse outside plugins_dir.
             timeout: Installation timeout in seconds
 
         Returns:
@@ -160,59 +254,42 @@ class PluginLoader:
 
         # Resolve to a canonical absolute path (normalises .. and symlinks)
         plugin_dir_real = os.path.realpath(str(plugin_dir))
+        plugins_dir_real = os.path.realpath(str(plugins_dir))
+        requested_name = os.path.basename(plugin_dir_real)
 
-        if plugins_dir is not None:
-            # Reconstruct the plugin path from a trusted base + a sanitised
-            # directory name.  os.path.basename() is CodeQL's recognised
-            # py/path-injection sanitiser: it strips all directory components
-            # so the result cannot contain traversal sequences.  Joining it
-            # with the resolved, trusted plugins_dir produces a path that
-            # CodeQL considers untainted.
-            plugins_dir_real = os.path.realpath(str(plugins_dir))
-            safe_dir_name = os.path.basename(plugin_dir_real)
-            if not safe_dir_name:
-                self.logger.error("Could not determine plugin directory name for %s", plugin_id)
-                return False
-            safe_plugin_dir = os.path.join(plugins_dir_real, safe_dir_name)
-            if not os.path.isdir(safe_plugin_dir):
-                self.logger.error(
-                    "Plugin directory for %s not found inside plugins dir", plugin_id
-                )
-                return False
-        else:
-            safe_plugin_dir = plugin_dir_real
-            if not os.path.isdir(safe_plugin_dir):
-                self.logger.error("Plugin directory does not exist: %s", plugin_dir)
-                return False
+        # Match the requested directory against an entry actually enumerated
+        # from the trusted plugins_dir, and build the path from that entry --
+        # not from requested_name. A name that came out of os.scandir() on a
+        # trusted root carries no taint regardless of what the caller asked
+        # for, so this is a real containment guarantee (an allowlist check
+        # against a trusted source), not a string-sanitisation of untrusted
+        # input that a static analyzer has to trust blindly.
+        matched_name = find_trusted_subdir(plugins_dir_real, requested_name)
+        if matched_name is None:
+            self.logger.error(
+                "Plugin directory for %s not found inside plugins dir", plugin_id
+            )
+            return False
 
+        safe_plugin_dir = os.path.join(plugins_dir_real, matched_name)
         requirements_file = os.path.join(safe_plugin_dir, "requirements.txt")
-        marker_file = os.path.join(safe_plugin_dir, ".dependencies_installed")
 
         if not os.path.isfile(requirements_file):
             return True  # No dependencies needed
 
-        try:
-            with open(requirements_file, 'rb') as fh:
-                current_hash = hashlib.sha256(fh.read()).hexdigest()
-        except OSError as e:
-            self.logger.error("Failed to read requirements.txt for %s: %s", plugin_id, e)
-            return False
+        if not requirements_has_real_deps(requirements_file):
+            self.logger.debug(
+                "requirements.txt for %s has no real dependencies (comments/blank only), skipping pip",
+                plugin_id
+            )
+            return True
 
-        # Skip if requirements.txt hasn't changed since last install
-        if os.path.isfile(marker_file):
-            try:
-                with open(marker_file, 'r', encoding='utf-8') as fh:
-                    stored_hash = fh.read().strip()
-            except OSError as e:
-                self.logger.warning(
-                    "Could not read dependency marker for %s (%s), will reinstall dependencies",
-                    plugin_id, e
-                )
-            else:
-                if stored_hash == current_hash:
-                    self.logger.debug("Dependencies already installed for %s (requirements unchanged)", plugin_id)
-                    return True
-                self.logger.info("Requirements changed for %s, reinstalling dependencies", plugin_id)
+        if requirements_are_satisfied(requirements_file):
+            self.logger.debug(
+                "Dependencies for %s already satisfied in current environment, skipping pip",
+                plugin_id
+            )
+            return True
 
         try:
             self.logger.info("Installing dependencies for plugin %s...", plugin_id)
@@ -225,32 +302,54 @@ class PluginLoader:
             )
 
             if result.returncode == 0:
-                try:
-                    with open(marker_file, 'w', encoding='utf-8') as fh:
-                        fh.write(current_hash)
-                    ensure_file_permissions(Path(marker_file), get_plugin_file_mode())
-                except OSError as marker_err:
-                    self.logger.debug("Could not write dependency marker for %s: %s", plugin_id, marker_err)
                 self.logger.info("Dependencies installed successfully for %s", plugin_id)
                 return True
             else:
                 stderr = result.stderr or ""
-                # uninstall-no-record-file means the package is already present at the
-                # system level (e.g. installed via dnf/apt without a pip RECORD file).
-                # pip can't replace it, but it IS installed — write the marker so we
-                # don't retry on every restart.
+                # uninstall-no-record-file means a system-managed copy of a package
+                # (e.g. apt's python3-requests, which ships no pip RECORD file) is in
+                # the way of the version this requirements.txt pins. Retry with
+                # --ignore-installed so pip lays the pinned version down alongside
+                # the system copy instead of trying to replace it — matching the
+                # retry already used by install_dependencies_apt.py / safe_pip_install.sh.
+                # Without this retry, the plugin would silently keep running against
+                # whatever version the system happened to ship.
                 if "uninstall-no-record-file" in stderr:
                     self.logger.warning(
-                        "Dependencies for %s include system-managed packages (no pip RECORD). "
-                        "Assuming they are satisfied: %s",
+                        "Dependencies for %s conflict with a system-managed package "
+                        "(no pip RECORD); retrying with --ignore-installed: %s",
                         plugin_id, stderr.strip()
                     )
+                    # Wrapped in its own try/except so a retry timeout is
+                    # tolerated the same way as a retry failure, instead of
+                    # propagating to the outer handler and returning False
+                    # (which would contradict the "assume satisfied" fallback
+                    # below).
                     try:
-                        with open(marker_file, 'w', encoding='utf-8') as fh:
-                            fh.write(current_hash)
-                        ensure_file_permissions(Path(marker_file), get_plugin_file_mode())
-                    except OSError as marker_err:
-                        self.logger.debug("Could not write dependency marker for %s: %s", plugin_id, marker_err)
+                        # sys.executable is this process's own interpreter (not
+                        # attacker-influenced), and requirements_file is a path
+                        # built internally by find_plugin_directory, never raw
+                        # external input.
+                        retry_result = subprocess.run(  # nosec B603 - no shell invoked (list-form argv)  # nosemgrep
+                            [sys.executable, "-m", "pip", "install", "--break-system-packages",
+                             "--ignore-installed", "-r", requirements_file],
+                            capture_output=True,
+                            text=True,
+                            timeout=timeout,
+                            check=False
+                        )
+                        if retry_result.returncode != 0:
+                            self.logger.warning(
+                                "Retry with --ignore-installed also failed for %s; assuming the "
+                                "system-managed version satisfies the requirement: %s",
+                                plugin_id, (retry_result.stderr or "").strip()
+                            )
+                    except subprocess.TimeoutExpired:
+                        self.logger.warning(
+                            "Retry with --ignore-installed timed out for %s; assuming the "
+                            "system-managed version satisfies the requirement",
+                            plugin_id
+                        )
                     return True
                 self.logger.warning(
                     "Dependency installation returned non-zero exit code for %s: %s",
@@ -338,8 +437,7 @@ class PluginLoader:
                 if not Path(existing_file).resolve().is_relative_to(resolved_dir):
                     evicted[mod_name] = sys.modules.pop(mod_name)
                     self.logger.debug(
-                        "Evicted stale module '%s' (from %s) before loading plugin in %s",
-                        mod_name, existing_file, plugin_dir,
+                        "Evicted stale bare-name module '%s' before loading plugin", mod_name,
                     )
             except (ValueError, TypeError):
                 continue
@@ -452,7 +550,7 @@ class PluginLoader:
             plugin_dir_str = str(plugin_dir)
             if plugin_dir_str not in sys.path:
                 sys.path.insert(0, plugin_dir_str)
-                self.logger.debug("Added plugin directory to sys.path: %s", plugin_dir_str)
+                self.logger.debug("Added plugin %s's directory to sys.path", plugin_id)
 
             # Import the plugin module
             module_name = f"plugin_{plugin_id.replace('-', '_')}"
@@ -464,8 +562,8 @@ class PluginLoader:
 
             spec = importlib.util.spec_from_file_location(module_name, entry_file)
             if spec is None or spec.loader is None:
+                self.logger.error("Could not create module spec for plugin %s", plugin_id)
                 error_msg = f"Could not create module spec for {entry_file}"
-                self.logger.error(error_msg)
                 raise PluginError(error_msg, plugin_id=plugin_id, context={'entry_file': str(entry_file)})
 
             module = importlib.util.module_from_spec(spec)
@@ -584,6 +682,55 @@ class PluginLoader:
             self.logger.error(error_msg, exc_info=True)
             raise PluginError(error_msg, plugin_id=plugin_id) from e
     
+    @staticmethod
+    def _parse_semver(value: Any) -> Optional[Tuple[int, int, int]]:
+        """Parse 'X.Y.Z' (extra parts/suffixes ignored) into a comparable
+        3-tuple, or None when unparseable."""
+        if not isinstance(value, str):
+            return None
+        parts = value.strip().lstrip('v').split('.')
+        try:
+            nums = [int(''.join(ch for ch in p if ch.isdigit()) or 0) for p in parts[:3]]
+        except ValueError:
+            return None
+        while len(nums) < 3:
+            nums.append(0)
+        return tuple(nums)  # type: ignore[return-value]
+
+    def _warn_if_incompatible(self, plugin_id: str, manifest: Dict[str, Any]) -> None:
+        """Log one warning when a plugin declares a minimum LEDMatrix version
+        newer than the running core. Advisory only — never raises — so a
+        plugin that guards optional features with try/except keeps working.
+        """
+        declared = (
+            manifest.get('min_ledmatrix_version')
+            or manifest.get('requires', {}).get('min_ledmatrix_version')
+        )
+        if not declared:
+            versions = manifest.get('versions') or []
+            if versions and isinstance(versions[0], dict):
+                declared = (versions[0].get('ledmatrix_min_version')
+                            or versions[0].get('ledmatrix_min'))
+        needed = self._parse_semver(declared)
+        if needed is None:
+            return
+
+        from src import __version__ as core_version
+        current = self._parse_semver(core_version)
+        # Anti-spam guard: if the core's own version number is stale (below
+        # the ecosystem floor every shipped plugin declares), comparing would
+        # warn on nearly everything — skip with a debug note instead.
+        if current is None or current < (2, 0, 0):
+            self.logger.debug(
+                "Skipping version compatibility check for %s: core __version__ "
+                "(%s) is below the ecosystem floor", plugin_id, core_version)
+            return
+        if needed > current:
+            self.logger.warning(
+                "Plugin %s declares min LEDMatrix version %s but this core is %s — "
+                "features it relies on may be missing; update the core or expect "
+                "degraded fallbacks", plugin_id, declared, core_version)
+
     def load_plugin(
         self,
         plugin_id: str,
@@ -616,8 +763,18 @@ class PluginLoader:
         Raises:
             PluginError: If loading fails
         """
+        self._warn_if_incompatible(plugin_id, manifest)
+
         # Install dependencies if needed
         if install_deps:
+            if plugins_dir is None:
+                raise PluginError(
+                    f"plugins_dir is required to install dependencies for plugin {plugin_id} "
+                    "(needed for path containment; pass install_deps=False if the caller "
+                    "doesn't have a trusted plugins directory to supply)",
+                    plugin_id=plugin_id,
+                    context={'plugin_dir': str(plugin_dir)},
+                )
             if not self.install_dependencies(plugin_dir, plugin_id, plugins_dir=plugins_dir):
                 raise PluginError(
                     f"Dependency installation failed for plugin {plugin_id} in {plugin_dir}",

src/plugin_system/plugin_manager.py

@@ -8,12 +8,13 @@ API Version: 1.0.0
 """
 
 import json
+import queue
 import sys
-import subprocess
 import time
 import threading
+import types
 from pathlib import Path
-from typing import Dict, List, Optional, Any
+from typing import Dict, List, Optional, Any, Tuple
 import logging
 from src.exceptions import PluginError, ConfigError
 from src.logging_config import get_logger
@@ -76,6 +77,12 @@ class PluginManager:
         # concurrent mutation (background reconciliation) and reads (requests).
         self._discovery_lock = threading.RLock()
 
+        # Lock protecting plugin_last_update from concurrent mutation/iteration.
+        # It's written from run_scheduled_updates()/update_all_plugins() (main
+        # loop) and read/diffed by run_scheduled_updates_with_changes(), which
+        # Vegas mode calls from its own background update-tick thread.
+        self._plugin_last_update_lock = threading.RLock()
+
         # Active plugins
         self.plugins: Dict[str, Any] = {}
         self.plugin_manifests: Dict[str, Dict[str, Any]] = {}
@@ -91,6 +98,50 @@ class PluginManager:
         # Health tracking (optional, set by display_controller if available)
         self.health_tracker = None
         self.resource_monitor = None
+
+        # --- Asynchronous plugin updates -------------------------------
+        # update() used to run inline in the render loop (execute_update's
+        # internal thread.join(timeout=30) blocked it), so one slow plugin
+        # HTTP fetch froze scrolling for the whole fetch. Scheduling still
+        # happens on the render thread (run_scheduled_updates), but
+        # execution moves to this single background worker. Per-plugin
+        # locks keep a plugin's update() and display() mutually exclusive —
+        # today's implicit guarantee, now explicit (and, unlike today,
+        # also held across the post-timeout window).
+        # Kill switch: plugin_system.synchronous_updates: true restores the
+        # inline path.
+        self._update_queue: "queue.Queue[Optional[Tuple[str, float]]]" = queue.Queue()
+        self._pending_updates: set = set()
+        self._pending_lock = threading.Lock()
+        self._plugin_locks: Dict[str, threading.Lock] = {}
+        self._plugin_locks_guard = threading.Lock()
+        self._update_worker: Optional[threading.Thread] = None
+        self._synchronous_updates = False
+        if self.config_manager is not None:
+            try:
+                cfg = self.config_manager.get_config() or {}
+            except (OSError, ValueError) as exc:
+                self.logger.warning(
+                    "Could not load config to check plugin_system.synchronous_updates "
+                    "(%s: %s); defaulting to synchronous updates", type(exc).__name__, exc)
+                self._synchronous_updates = True
+            else:
+                plugin_system_cfg = cfg.get('plugin_system', {})
+                if not isinstance(plugin_system_cfg, dict):
+                    self.logger.warning(
+                        "config plugin_system must be a mapping, got %s; "
+                        "defaulting to synchronous updates",
+                        type(plugin_system_cfg).__name__)
+                    self._synchronous_updates = True
+                else:
+                    sync_value = plugin_system_cfg.get('synchronous_updates', False)
+                    if not isinstance(sync_value, bool):
+                        self.logger.warning(
+                            "config plugin_system.synchronous_updates must be a boolean, "
+                            "got %r; defaulting to synchronous updates", sync_value)
+                        self._synchronous_updates = True
+                    else:
+                        self._synchronous_updates = sync_value
         
         # Ensure plugins directory exists with proper permissions
         try:
@@ -177,90 +228,6 @@ class PluginManager:
 
         return plugin_ids
 
-    def _get_dependency_marker_path(self, plugin_id: str) -> Path:
-        """Get path to dependency installation marker file."""
-        plugin_dir = self.plugins_dir / plugin_id
-        if not plugin_dir.exists():
-            # Try with ledmatrix- prefix
-            plugin_dir = self.plugins_dir / f"ledmatrix-{plugin_id}"
-        return plugin_dir / ".dependencies_installed"
-
-    def _check_dependencies_installed(self, plugin_id: str) -> bool:
-        """Check if dependencies are already installed for a plugin."""
-        marker_path = self._get_dependency_marker_path(plugin_id)
-        return marker_path.exists()
-
-    def _mark_dependencies_installed(self, plugin_id: str) -> None:
-        """Mark dependencies as installed for a plugin."""
-        marker_path = self._get_dependency_marker_path(plugin_id)
-        try:
-            marker_path.touch()
-            # Set proper file permissions after creating marker
-            from src.common.permission_utils import (
-                ensure_file_permissions,
-                get_plugin_file_mode
-            )
-            ensure_file_permissions(marker_path, get_plugin_file_mode())
-        except (OSError, PermissionError) as e:
-            self.logger.warning("Could not create dependency marker for %s: %s", plugin_id, e)
-
-    def _remove_dependency_marker(self, plugin_id: str) -> None:
-        """Remove dependency installation marker."""
-        marker_path = self._get_dependency_marker_path(plugin_id)
-        try:
-            if marker_path.exists():
-                marker_path.unlink()
-        except (OSError, PermissionError) as e:
-            self.logger.warning("Could not remove dependency marker for %s: %s", plugin_id, e)
-
-    def _install_plugin_dependencies(self, requirements_file: Path) -> bool:
-        """
-        Install plugin dependencies from requirements.txt.
-        
-        Args:
-            requirements_file: Path to requirements.txt
-            
-        Returns:
-            True if installation succeeded or not needed, False on error
-        """
-        try:
-            self.logger.info("Installing dependencies from %s", requirements_file)
-            result = subprocess.run(
-                [sys.executable, "-m", "pip", "install", "--break-system-packages", "--no-cache-dir", "-r", str(requirements_file)],
-                capture_output=True,
-                text=True,
-                timeout=300,
-                check=False
-            )
-            
-            if result.returncode == 0:
-                self.logger.info("Dependencies installed successfully")
-                return True
-            else:
-                self.logger.warning("Dependency installation returned non-zero exit code: %s", result.stderr)
-                return False
-        except subprocess.TimeoutExpired:
-            self.logger.error("Dependency installation timed out")
-            return False
-        except FileNotFoundError as e:
-            self.logger.warning("Command not found: %s. Skipping dependency installation", e)
-            return True
-        except (BrokenPipeError, OSError) as e:
-            # Handle broken pipe errors (errno 32) which can occur during pip downloads
-            # Often caused by network interruptions or output buffer issues
-            if isinstance(e, OSError) and e.errno == 32:
-                self.logger.error(
-                    "Broken pipe error during dependency installation. "
-                    "This usually indicates a network interruption or pip output buffer issue. "
-                    "Try installing again or check your network connection."
-                )
-            else:
-                self.logger.error("OS error during dependency installation: %s", e)
-            return False
-        except Exception as e:
-            self.logger.error("Unexpected error installing dependencies: %s", e, exc_info=True)
-            return True
-
     def load_plugin(self, plugin_id: str) -> bool:
         """
         Load a plugin by ID.
@@ -390,10 +357,19 @@ class PluginManager:
                     self.logger.error("Error validating plugin %s config: %s", plugin_id, e, exc_info=True)
                     self.state_manager.set_state(plugin_id, PluginState.ERROR, error=e)
                     return False
-            
+
+            # Schema validation (warn/degrade only — never blocks loading).
+            # A config that violates the plugin's JSON schema is surfaced to the
+            # user (log warning + degraded flag in the health tracker) but the
+            # plugin still loads exactly as it does today. This deliberately does
+            # NOT change load_plugin()'s pass/fail behaviour for any plugin that
+            # loads under the current code.
+            self._validate_config_schema_soft(plugin_id, config)
+
             # Store plugin instance
             self.plugins[plugin_id] = plugin_instance
-            self.plugin_last_update[plugin_id] = 0.0
+            with self._plugin_last_update_lock:
+                self.plugin_last_update[plugin_id] = 0.0
             # Invalidate cached interval so next tick re-derives it for this plugin
             self._update_interval_cache.pop(plugin_id, None)
             
@@ -419,6 +395,59 @@ class PluginManager:
             self.state_manager.set_state(plugin_id, PluginState.ERROR, error=e)
             return False
     
+    def _validate_config_schema_soft(self, plugin_id: str, config: Dict[str, Any]) -> None:
+        """Validate a plugin's config against its JSON schema — warn/degrade only.
+
+        On a schema violation this logs a warning and marks the plugin degraded
+        in the health tracker (when one is wired), so the problem is visible in
+        the web UI. It never raises, never changes plugin state, and never
+        affects whether the plugin loads. ``config`` here has already been
+        merged with schema defaults by the caller, so fields that ship a default
+        never appear "missing" — only genuinely user-supplied required fields
+        (e.g. an API key) can trip the required-field check.
+        """
+        try:
+            schema = self.schema_manager.load_schema(plugin_id)
+        except Exception as e:  # pragma: no cover - defensive
+            self.logger.debug("Could not load schema for %s: %s", plugin_id, e)
+            return
+
+        if not schema:
+            # No schema shipped — nothing to validate. Clear any stale flag.
+            self._set_degraded_safe(plugin_id, None)
+            return
+
+        try:
+            is_valid, errors = self.schema_manager.validate_config_against_schema(
+                config, schema, plugin_id
+            )
+        except Exception as e:  # pragma: no cover - defensive
+            # Validation machinery itself failed — do not penalise the plugin.
+            self.logger.debug("Schema validation raised for %s: %s", plugin_id, e)
+            return
+
+        if is_valid or not errors:
+            self._set_degraded_safe(plugin_id, None)
+            return
+
+        summary = "; ".join(errors[:5])
+        if len(errors) > 5:
+            summary += f" (+{len(errors) - 5} more)"
+        self.logger.warning(
+            "Plugin %s config does not match its schema (loading anyway): %s",
+            plugin_id, summary,
+        )
+        self._set_degraded_safe(plugin_id, f"Config schema: {summary}")
+
+    def _set_degraded_safe(self, plugin_id: str, reason: Optional[str]) -> None:
+        """Best-effort ``health_tracker.set_degraded`` that never raises."""
+        if not self.health_tracker:
+            return
+        try:
+            self.health_tracker.set_degraded(plugin_id, reason)
+        except Exception as e:  # pragma: no cover - defensive
+            self.logger.debug("Could not set degraded flag for %s: %s", plugin_id, e)
+
     def unload_plugin(self, plugin_id: str) -> bool:
         """
         Unload a plugin by ID.
@@ -452,7 +481,8 @@ class PluginManager:
             
             # Remove from active plugins
             del self.plugins[plugin_id]
-            self.plugin_last_update.pop(plugin_id, None)
+            with self._plugin_last_update_lock:
+                self.plugin_last_update.pop(plugin_id, None)
             self._update_interval_cache.pop(plugin_id, None)
             
             # Remove main module from sys.modules if present
@@ -721,7 +751,8 @@ class PluginManager:
             'recoverable': True,
         }
         self.logger.warning("Plugin %s update() failed; will retry after interval", plugin_id)
-        self.plugin_last_update[plugin_id] = failure_time
+        with self._plugin_last_update_lock:
+            self.plugin_last_update[plugin_id] = failure_time
         self.state_manager.set_state_with_error(plugin_id, PluginState.ENABLED, error_info, error=err)
         if self.health_tracker:
             self.health_tracker.record_failure(plugin_id, err)
@@ -754,39 +785,218 @@ class PluginManager:
             if interval is None:
                 continue
 
-            last_update = self.plugin_last_update.get(plugin_id, 0.0)
+            with self._plugin_last_update_lock:
+                last_update = self.plugin_last_update.get(plugin_id, 0.0)
 
             if last_update == 0.0 or (current_time - last_update) >= interval:
-                # Update state to RUNNING
-                self.state_manager.set_state(plugin_id, PluginState.RUNNING)
-                
-                try:
-                    # Use PluginExecutor for safe execution
-                    success = False
-                    if self.resource_monitor:
-                        # If resource monitor exists, wrap the call
-                        def monitored_update():
-                            self.resource_monitor.monitor_call(plugin_id, plugin_instance.update)
-                        success = self.plugin_executor.execute_update(
-                            type('obj', (object,), {'update': monitored_update})(),
-                            plugin_id
-                        )
-                    else:
-                        success = self.plugin_executor.execute_update(plugin_instance, plugin_id)
-                    
-                    if success:
-                        self.plugin_last_update[plugin_id] = current_time
-                        self.state_manager.record_update(plugin_id)
-                        # Update state back to ENABLED
-                        self.state_manager.set_state(plugin_id, PluginState.ENABLED)
-                        # Record success
-                        if self.health_tracker:
-                            self.health_tracker.record_success(plugin_id)
-                    else:
-                        self._record_update_failure(plugin_id)
-                except Exception as exc:  # pylint: disable=broad-except
-                    self.logger.exception("Error updating plugin %s: %s", plugin_id, exc)
+                if self._synchronous_updates:
+                    # Kill-switch path: the original inline execution
+                    # (blocks the caller until update() completes/times out)
+                    self.state_manager.set_state(plugin_id, PluginState.RUNNING)
+                    self._execute_update_now(plugin_id, plugin_instance, current_time)
+                else:
+                    self._enqueue_update(plugin_id, current_time)
+
+    def get_plugin_lock(self, plugin_id: str) -> threading.Lock:
+        """Per-plugin lock keeping update() and display() mutually exclusive.
+
+        The update worker holds it for the duration of a plugin's update();
+        the display side acquires it non-blocking and skips that frame's
+        display() call when the plugin is mid-update.
+        """
+        with self._plugin_locks_guard:
+            lock = self._plugin_locks.get(plugin_id)
+            if lock is None:
+                lock = threading.Lock()
+                self._plugin_locks[plugin_id] = lock
+            return lock
+
+    def _enqueue_update(self, plugin_id: str, scheduled_time: float) -> None:
+        """Queue a due update for the background worker (dedup while pending)."""
+        with self._pending_lock:
+            if plugin_id in self._pending_updates:
+                return
+            self._pending_updates.add(plugin_id)
+        # RUNNING is set at enqueue time so can_execute() blocks re-entry and
+        # the web UI shows the truthful state while the item waits its turn.
+        self.state_manager.set_state(plugin_id, PluginState.RUNNING)
+        self._ensure_update_worker()
+        self._update_queue.put((plugin_id, scheduled_time))
+
+    def _ensure_update_worker(self) -> None:
+        if self._update_worker is not None and self._update_worker.is_alive():
+            return
+        self._update_worker = threading.Thread(
+            target=self._update_worker_loop, name='plugin-update-worker',
+            daemon=True)
+        self._update_worker.start()
+
+    def _update_worker_loop(self) -> None:
+        """Single worker: dispatches queued updates off the render thread
+        (matching the old inline behavior — no thundering herd of
+        concurrent fetches).
+
+        The plugin's lock is acquired here, before its instance is looked
+        up, and the instance is re-fetched under the lock — a concurrent
+        unload_plugin() can't leave this loop about to run update() on an
+        instance that's already been torn down. The lock — and RUNNING/
+        pending lifecycle state — is released by the update itself once the
+        real update() call genuinely finishes (see _execute_update_now),
+        which can be after this dispatch returns if PluginExecutor's own
+        timeout elapses first.
+        """
+        while True:
+            item = self._update_queue.get()
+            if item is None:  # shutdown sentinel
+                return
+            plugin_id, scheduled_time = item
+            lock = self.get_plugin_lock(plugin_id)
+            lock.acquire()
+            plugin_instance = self.plugins.get(plugin_id)
+            if plugin_instance is None:  # unloaded while queued; its
+                # lifecycle state was already cleared by unload_plugin —
+                # leave it alone rather than resurrecting it to ENABLED
+                lock.release()
+                with self._pending_lock:
+                    self._pending_updates.discard(plugin_id)
+                continue
+            try:
+                self._execute_update_now(plugin_id, plugin_instance,
+                                         scheduled_time, lock=lock)
+            except Exception:  # pylint: disable=broad-except
+                # _execute_update_now guarantees the lock/pending bookkeeping
+                # is released via its own _finish() before returning or
+                # raising; this is a last-resort log only.
+                self.logger.exception("update worker: unexpected error for %s",
+                                      plugin_id)
+
+    def stop_update_worker(self, timeout: float = 5.0) -> None:
+        """Signal the worker to exit (used by cleanup; thread is a daemon)."""
+        if self._update_worker is not None and self._update_worker.is_alive():
+            self._update_queue.put(None)
+            self._update_worker.join(timeout=timeout)
+            if self._update_worker.is_alive():
+                self.logger.warning(
+                    "Update worker did not stop within %.1fs; it is a daemon "
+                    "thread and will be abandoned on shutdown", timeout)
+
+    def _execute_update_now(self, plugin_id: str, plugin_instance: Any,
+                            scheduled_time: float,
+                            lock: Optional[threading.Lock] = None) -> None:
+        """Execute a plugin's update() via PluginExecutor, then bookkeep.
+
+        Caller is responsible for having set RUNNING state.
+
+        On the synchronous path (``lock=None``) this is the original,
+        unchanged inline behavior. On the async worker path, PluginExecutor's
+        internal thread.join(timeout) blocks only the calling thread -- on
+        timeout the lingering daemon update-thread keeps running the real
+        plugin.update() call unkillable in the background. So that the
+        plugin's lock (and its RUNNING/pending lifecycle state) stays held
+        for that real duration rather than just this bounded wait, ownership
+        of both is carried by the wrapped update callable itself, released
+        from whichever thread actually finishes it -- see _finish() below.
+        """
+        finish_guard = threading.Lock()
+        finished = {'done': False}
+
+        def _finish(success: bool, exc: Optional[Exception] = None) -> None:
+            with finish_guard:
+                if finished['done']:
+                    return
+                finished['done'] = True
+            try:
+                if success:
+                    with self._plugin_last_update_lock:
+                        self.plugin_last_update[plugin_id] = scheduled_time
+                    self.state_manager.record_update(plugin_id)
+                    self.state_manager.set_state(plugin_id, PluginState.ENABLED)
+                    if self.health_tracker:
+                        self.health_tracker.record_success(plugin_id)
+                else:
                     self._record_update_failure(plugin_id, exc=exc)
+            finally:
+                if lock is not None:
+                    lock.release()
+                    with self._pending_lock:
+                        self._pending_updates.discard(plugin_id)
+
+        if lock is None:
+            # Synchronous / no-lock path: unchanged behavior.
+            try:
+                if self.resource_monitor:
+                    def monitored_update():
+                        self.resource_monitor.monitor_call(plugin_id, plugin_instance.update)
+                    # SimpleNamespace stores `update` as an *instance*
+                    # attribute, so attribute lookup returns the plain
+                    # function object as-is. A dynamically-built class
+                    # (`type(..., {'update': monitored_update})`) instead
+                    # stores it as a *class* attribute, which the
+                    # descriptor protocol turns into a bound method on
+                    # access -- silently prepending the instance as an
+                    # implicit first argument to a function that takes
+                    # none, raising "monitored_update() takes 0
+                    # positional arguments but 1 was given" on every call.
+                    success = self.plugin_executor.execute_update(
+                        types.SimpleNamespace(update=monitored_update),
+                        plugin_id
+                    )
+                else:
+                    success = self.plugin_executor.execute_update(plugin_instance, plugin_id)
+                _finish(success)
+            except Exception as exc:  # pylint: disable=broad-except
+                self.logger.exception("Error updating plugin %s: %s", plugin_id, exc)
+                _finish(False, exc=exc)
+            return
+
+        # Async worker path: the real update() call -- through the resource
+        # monitor, if configured -- owns finishing the lock/lifecycle
+        # bookkeeping, from whichever thread actually runs it to completion.
+        def _target_update() -> None:
+            try:
+                if self.resource_monitor:
+                    self.resource_monitor.monitor_call(plugin_id, plugin_instance.update)
+                else:
+                    plugin_instance.update()
+            except Exception as exc:
+                _finish(False, exc=exc)
+                raise
+            else:
+                _finish(True)
+
+        try:
+            self.plugin_executor.execute_update(
+                types.SimpleNamespace(update=_target_update), plugin_id)
+        except Exception as exc:  # pragma: no cover - defensive; execute_update
+            # catches everything internally, but guarantee _finish still
+            # runs (releasing the lock) if something unexpected slips through.
+            self.logger.exception("Unexpected error dispatching update for %s: %s", plugin_id, exc)
+            _finish(False, exc=exc)
+
+    def run_scheduled_updates_with_changes(self, current_time: Optional[float] = None) -> List[str]:
+        """
+        Like run_scheduled_updates(), but also returns the plugin_ids whose
+        plugin_last_update timestamp actually advanced during this call.
+
+        The before/after snapshots and the update pass itself are each
+        individually lock-protected against concurrent plugin_last_update
+        mutation (Vegas mode calls this from its own background
+        update-tick thread, racing the main render loop's plugin updates),
+        so callers get an atomic "who got fresh data" answer without
+        reaching into plugin_last_update themselves. The lock is not held
+        across the update pass so slow/blocking plugin update() calls don't
+        serialize against other plugin_last_update readers.
+        """
+        with self._plugin_last_update_lock:
+            old_times = dict(self.plugin_last_update)
+
+        self.run_scheduled_updates(current_time)
+
+        with self._plugin_last_update_lock:
+            return [
+                plugin_id for plugin_id, new_time in self.plugin_last_update.items()
+                if new_time > old_times.get(plugin_id, 0.0)
+            ]
 
     def update_all_plugins(self) -> None:
         """
@@ -810,7 +1020,8 @@ class PluginManager:
             try:
                 success = self.plugin_executor.execute_update(plugin_instance, plugin_id)
                 if success:
-                    self.plugin_last_update[plugin_id] = time.time()
+                    with self._plugin_last_update_lock:
+                        self.plugin_last_update[plugin_id] = time.time()
                     self.state_manager.record_update(plugin_id)
                     self.state_manager.set_state(plugin_id, PluginState.ENABLED)
                 else:
@@ -836,7 +1047,7 @@ class PluginManager:
             
             # Get health tracker metrics if available
             if self.health_tracker:
-                health_info = self.health_tracker.get_plugin_health(plugin_id)
+                health_info = self.health_tracker.get_health_summary(plugin_id)
                 plugin_metrics['health'] = health_info
             else:
                 plugin_metrics['health'] = {'status': 'unknown'}
@@ -861,7 +1072,7 @@ class PluginManager:
             
             # Get resource monitor metrics if available
             if self.resource_monitor:
-                resource_info = self.resource_monitor.get_plugin_metrics(plugin_id)
+                resource_info = self.resource_monitor.get_metrics_summary(plugin_id)
                 plugin_metrics['resources'] = resource_info
             else:
                 plugin_metrics['resources'] = {'status': 'unknown'}

src/plugin_system/resource_monitor.py

@@ -71,17 +71,32 @@ class PluginResourceMonitor:
         self.cache_manager = cache_manager
         self.enable_monitoring = enable_monitoring and PSUTIL_AVAILABLE
         self.logger = logging.getLogger(__name__)
-        
+
         # Resource metrics per plugin
         self._metrics: Dict[str, ResourceMetrics] = {}
         self._limits: Dict[str, ResourceLimits] = {}
-        
+
         # Thread-local storage for execution tracking
         self._local = threading.local()
-        
+
         # Lock for thread-safe access
         self._lock = threading.Lock()
-        
+
+        # Cache a single psutil.Process handle. Reusing the same handle is what
+        # lets cpu_percent() be read non-blocking (interval=None): psutil returns
+        # the utilisation since the *previous* call on that same object. Creating
+        # a fresh Process() per call would force interval-based sampling that
+        # blocks the caller — unacceptable on the display loop's update path.
+        self._process = None
+        if self.enable_monitoring:
+            try:
+                self._process = psutil.Process()
+                # Prime cpu_percent so the first real measurement returns a
+                # meaningful delta instead of 0.0.
+                self._process.cpu_percent(interval=None)
+            except Exception:  # pragma: no cover - psutil edge cases
+                self._process = None
+
         if not PSUTIL_AVAILABLE and enable_monitoring:
             self.logger.warning(
                 "psutil not available - resource monitoring will be limited to execution time only"
@@ -95,13 +110,21 @@ class PluginResourceMonitor:
         """Get cache key for plugin limits."""
         return f"plugin_limits:{plugin_id}"
     
-    def get_metrics(self, plugin_id: str) -> ResourceMetrics:
-        """Get current metrics for a plugin."""
+    def get_metrics(self, plugin_id: str, force_reload: bool = False) -> ResourceMetrics:
+        """Get current metrics for a plugin.
+
+        ``force_reload=True`` bypasses both the in-memory copy and the cache
+        manager's memory tier so a read-only consumer (e.g. the web process)
+        sees the writer process's latest persisted metrics rather than a stale
+        first snapshot.
+        """
         with self._lock:
-            if plugin_id not in self._metrics:
+            if force_reload or plugin_id not in self._metrics:
                 # Try to load from cache
                 cache_key = self._get_metrics_key(plugin_id)
-                cached = self.cache_manager.get(cache_key, max_age=None)
+                cached = self.cache_manager.get(
+                    cache_key, max_age=None, memory_ttl=0 if force_reload else None
+                )
                 if cached:
                     metrics = ResourceMetrics(**cached)
                 else:
@@ -137,21 +160,24 @@ class PluginResourceMonitor:
     
     def _get_process_memory_mb(self) -> float:
         """Get current process memory usage in MB."""
-        if not self.enable_monitoring:
+        if not self.enable_monitoring or self._process is None:
             return 0.0
         try:
-            process = psutil.Process()
-            return process.memory_info().rss / 1024 / 1024
+            return self._process.memory_info().rss / 1024 / 1024
         except Exception:
             return 0.0
-    
-    def _get_process_cpu_percent(self, interval: float = 0.1) -> float:
-        """Get current process CPU usage percentage."""
-        if not self.enable_monitoring:
+
+    def _get_process_cpu_percent(self) -> float:
+        """Get current process CPU usage percentage (non-blocking).
+
+        Reads cpu_percent(interval=None) against the cached process handle, so
+        it returns immediately with the utilisation observed since the previous
+        call rather than blocking to sample a fresh interval.
+        """
+        if not self.enable_monitoring or self._process is None:
             return 0.0
         try:
-            process = psutil.Process()
-            return process.cpu_percent(interval=interval)
+            return self._process.cpu_percent(interval=None)
         except Exception:
             return 0.0
     
@@ -281,9 +307,13 @@ class PluginResourceMonitor:
             self.logger.error(error_msg)
             raise ResourceLimitExceeded(error_msg)
     
-    def get_metrics_summary(self, plugin_id: str) -> Dict[str, Any]:
-        """Get metrics summary for a plugin."""
-        metrics = self.get_metrics(plugin_id)
+    def get_metrics_summary(self, plugin_id: str, force_reload: bool = False) -> Dict[str, Any]:
+        """Get metrics summary for a plugin.
+
+        ``force_reload=True`` refreshes from the persisted cache first so
+        cross-process readers reflect the writer's latest metrics.
+        """
+        metrics = self.get_metrics(plugin_id, force_reload=force_reload)
         limits = self.get_limits(plugin_id)
         
         avg_execution_time = 0.0

src/plugin_system/store_manager.py

@@ -5,7 +5,6 @@ Handles plugin discovery, installation, updates, and uninstallation
 from both the official registry and custom GitHub repositories.
 """
 
-import hashlib
 import os
 import re
 import json
@@ -25,7 +24,10 @@ import logging
 
 from urllib.parse import urlparse
 
-from src.common.permission_utils import sudo_remove_directory
+from src.common.permission_utils import sudo_remove_directory, install_requirements_file
+from src.plugin_system.plugin_loader import (
+    requirements_has_real_deps, requirements_are_satisfied, find_trusted_subdir
+)
 
 try:
     from jsonschema import Draft7Validator, ValidationError
@@ -140,9 +142,28 @@ class PluginStoreManager:
         # then get the result from the warm cache (double-checked locking).
         self._registry_fetch_lock = threading.Lock()
 
+        # Per-plugin locks for _reinstall_with_rollback: the web UI runs
+        # Flask with threaded=True, so two overlapping requests for the
+        # same plugin_id (double-click, two browser tabs) would otherwise
+        # both rename the same directory aside — one succeeds, and the
+        # loser can end up renaming the winner's in-progress install aside
+        # mid-download, stealing its own rollback safety net. Keyed by
+        # plugin_id so unrelated plugins still update concurrently.
+        self._reinstall_locks: Dict[str, threading.Lock] = {}
+        self._reinstall_locks_guard = threading.Lock()
+
         # Ensure plugins directory exists
         self.plugins_dir.mkdir(exist_ok=True)
 
+    def _get_reinstall_lock(self, plugin_id: str) -> threading.Lock:
+        """Lazily create (or fetch) the per-plugin reinstall lock."""
+        with self._reinstall_locks_guard:
+            lock = self._reinstall_locks.get(plugin_id)
+            if lock is None:
+                lock = threading.Lock()
+                self._reinstall_locks[plugin_id] = lock
+            return lock
+
     def _record_cache_backoff(self, cache_dict: Dict, cache_key: str,
                               cache_timeout: int, payload: Any) -> None:
         """Bump a cache entry's timestamp so subsequent lookups hit the
@@ -1900,40 +1921,63 @@ class PluginStoreManager:
     def _install_dependencies(self, plugin_path: Path) -> bool:
         """
         Install Python dependencies from requirements.txt.
-        
+
         Args:
             plugin_path: Path to plugin directory
-            
+
         Returns:
             True if successful or no requirements file
         """
-        requirements_file = plugin_path / "requirements.txt"
-        
+        # Reconstruct the plugin path from the trusted self.plugins_dir base +
+        # an entry actually enumerated from it, rather than trusting
+        # plugin_path directly -- callers ultimately derive it from a
+        # plugin-supplied manifest "id" field (see install_plugin_from_url),
+        # so without this a malicious manifest could point requirements_file
+        # outside plugins_dir. find_trusted_subdir()'s return value always
+        # comes from os.scandir() on the trusted root, so building the path
+        # from it (not from the caller's string) is a real containment
+        # guarantee, matching the pattern in PluginLoader.install_dependencies().
+        plugin_dir_real = os.path.realpath(str(plugin_path))
+        plugins_dir_real = os.path.realpath(str(self.plugins_dir))
+        requested_name = os.path.basename(plugin_dir_real)
+        matched_name = find_trusted_subdir(plugins_dir_real, requested_name)
+        if matched_name is None:
+            self.logger.error("Plugin directory not found inside plugins dir for dependency install")
+            return False
+        safe_plugin_path = Path(os.path.join(plugins_dir_real, matched_name))
+
+        requirements_file = safe_plugin_path / "requirements.txt"
+
         if not requirements_file.exists():
             self.logger.debug(f"No requirements.txt found in {plugin_path.name}")
             return True
-        
+
+        if not requirements_has_real_deps(str(requirements_file)):
+            self.logger.debug(f"requirements.txt for {plugin_path.name} has no real dependencies, skipping pip")
+            return True
+
+        if requirements_are_satisfied(str(requirements_file)):
+            self.logger.debug(f"Dependencies for {plugin_path.name} already satisfied, skipping pip")
+            return True
+
         try:
             self.logger.info(f"Installing dependencies for {plugin_path.name}")
-            subprocess.run(
-                ['pip3', 'install', '--break-system-packages', '-r', str(requirements_file)],
-                check=True,
-                capture_output=True,
-                text=True,
-                timeout=300
-            )
+            # Routed through the shared root-visible installer (same one the
+            # web UI's "Reinstall Plugin Deps" tool uses) rather than a bare
+            # `pip`/`pip3` off PATH: a bare pip binary can silently resolve to
+            # a different Python installation than the one that actually runs
+            # ledmatrix.service, so pip reports success while the package
+            # stays invisible to the running plugin (e.g. missing `astral`
+            # for the weather plugin even though "install" succeeded).
+            result = install_requirements_file(requirements_file, timeout=300)
+            if result.returncode != 0:
+                self.logger.error(
+                    f"Error installing dependencies for {plugin_path.name}: {result.stderr}"
+                )
+                return False
             self.logger.info(f"Dependencies installed successfully for {plugin_path.name}")
-            # Write hash marker so plugin_loader skips redundant pip run on next startup
-            try:
-                current_hash = hashlib.sha256(requirements_file.read_bytes()).hexdigest()
-                (plugin_path / ".dependencies_installed").write_text(current_hash, encoding='utf-8')
-            except OSError as marker_err:
-                self.logger.debug("Could not write dependency marker for %s: %s", plugin_path.name, marker_err)
             return True
-            
-        except subprocess.CalledProcessError as e:
-            self.logger.error(f"Error installing dependencies: {e.stderr}")
-            return False
+
         except subprocess.TimeoutExpired:
             self.logger.error("Dependency installation timed out")
             return False
@@ -2238,6 +2282,74 @@ class PluginStoreManager:
             self.logger.error(f"Error uninstalling plugin {plugin_id}: {e}")
             return False
     
+    def _reinstall_with_rollback(self, plugin_id: str, plugin_path: Path) -> bool:
+        """Replace an installed plugin with a fresh install, atomically.
+
+        The old install is renamed aside (not deleted) until the new install
+        succeeds, then removed; on ANY install failure the old directory is
+        restored. This is the difference between a failed update and a
+        destroyed plugin: the previous delete-then-install flow permanently
+        removed plugins whenever the download failed mid-update (seen in the
+        field during the monorepo migration on a Pi with broken DNS — every
+        old-remote plugin was deleted and none could be re-downloaded).
+
+        The aside name embeds '.standalone-backup-' so plugin discovery
+        (plugin_manager._scan_directory_for_plugins) ignores it even though
+        it still contains a manifest.json.
+
+        Held for the whole operation under a per-plugin_id lock: two
+        overlapping requests for the same plugin (double-click, two
+        browser tabs — the web UI runs Flask with threaded=True) must not
+        interleave their renames, or the second could steal the first's
+        rollback safety net mid-install. Other plugin_ids are unaffected.
+        """
+        with self._get_reinstall_lock(plugin_id):
+            backup_path = plugin_path.with_name(
+                f"{plugin_path.name}.standalone-backup-migrating")
+            # A stale aside from a previous crash would block the rename
+            if backup_path.exists():
+                if not self._safe_remove_directory(backup_path):
+                    self.logger.error(
+                        f"Could not clear stale backup for {plugin_id} at "
+                        f"{backup_path}; leaving old install in place")
+                    return False
+            try:
+                plugin_path.rename(backup_path)
+            except OSError as e:
+                self.logger.error(
+                    f"Could not set aside old plugin directory for {plugin_id}: {e}")
+                return False
+
+            try:
+                installed = self.install_plugin(plugin_id)
+            except Exception as e:
+                self.logger.error(f"Reinstall of {plugin_id} raised: {e}")
+                installed = False
+
+            if installed:
+                if not self._safe_remove_directory(backup_path):
+                    self.logger.warning(
+                        f"Update of {plugin_id} succeeded but the old backup "
+                        f"at {backup_path} could not be removed; it will be "
+                        f"cleared on the next update")
+                return True
+
+            # Install failed (bad network, registry error...) — put the old
+            # version back so the user still has a working plugin.
+            self.logger.error(
+                f"Reinstall of {plugin_id} failed; restoring previous version")
+            try:
+                if plugin_path.exists():
+                    # partial download debris from the failed install
+                    self._safe_remove_directory(plugin_path)
+                backup_path.rename(plugin_path)
+                self.logger.info(f"Restored previous install of {plugin_id}")
+            except OSError as e:
+                self.logger.error(
+                    f"CRITICAL: could not restore {plugin_id} from {backup_path}: {e}. "
+                    f"The previous install is preserved there — rename it back manually.")
+            return False
+
     def update_plugin(self, plugin_id: str) -> bool:
         """
         Update a plugin to the latest commit on its upstream branch.
@@ -2300,10 +2412,7 @@ class PluginStoreManager:
                             f"Plugin {resolved_id} git remote ({local_remote}) differs from registry ({registry_repo}). "
                             f"Reinstalling from registry to migrate to new source."
                         )
-                        if not self._safe_remove_directory(plugin_path):
-                            self.logger.error(f"Failed to remove old plugin directory for {resolved_id}")
-                            return False
-                        return self.install_plugin(resolved_id)
+                        return self._reinstall_with_rollback(resolved_id, plugin_path)
 
                     # Check if already up to date
                     if remote_sha and local_sha and remote_sha.startswith(local_sha):
@@ -2429,19 +2538,6 @@ class PluginStoreManager:
                                     file_path = line[3:].strip()
                                     untracked_files.append(file_path)
                         
-                        # Remove marker files that are safe to delete (they'll be regenerated)
-                        safe_to_remove = ['.dependencies_installed']
-                        removed_files = []
-                        for file_name in safe_to_remove:
-                            file_path = plugin_path / file_name
-                            if file_path.exists() and file_name in untracked_files:
-                                try:
-                                    file_path.unlink()
-                                    removed_files.append(file_name)
-                                    self.logger.info(f"Removed marker file {file_name} from {plugin_id} before update")
-                                except Exception as e:
-                                    self.logger.warning(f"Could not remove {file_name} from {plugin_id}: {e}")
-                        
                         # Check for tracked file changes
                         status_result = subprocess.run(
                             ['git', '-C', str(plugin_path), 'status', '--porcelain', '--untracked-files=no'],
@@ -2452,10 +2548,9 @@ class PluginStoreManager:
                         )
                         has_changes = bool(status_result.stdout.strip())
                         
-                        # If there are remaining untracked files (not safe to remove), stash them
-                        remaining_untracked = [f for f in untracked_files if f not in removed_files]
-                        if remaining_untracked:
-                            self.logger.info(f"Found {len(remaining_untracked)} untracked files in {plugin_id}, will stash them")
+                        # If there are untracked files, stash them
+                        if untracked_files:
+                            self.logger.info(f"Found {len(untracked_files)} untracked files in {plugin_id}, will stash them")
                             has_changes = True
                     except subprocess.TimeoutExpired:
                         # If status check times out, assume there might be changes and proceed
@@ -2621,11 +2716,11 @@ class PluginStoreManager:
             # Plugin is not a git repo but is in registry and has a newer version - reinstall
             self.logger.info(f"Plugin {plugin_id} not installed via git; re-installing latest archive (registry id: {registry_id})")
 
-            # Remove directory and reinstall fresh
-            if not self._safe_remove_directory(plugin_path):
-                self.logger.error(f"Failed to remove old plugin directory for {plugin_id}")
-                return False
-            return self.install_plugin(registry_id)
+            # Reinstall with the old version kept aside until the new
+            # download succeeds — this is the path every routine store
+            # update takes, and a mid-update network failure must not
+            # destroy the user's plugin.
+            return self._reinstall_with_rollback(registry_id, plugin_path)
 
         except Exception as e:
             import traceback

src/plugin_system/testing/bounds_display_manager.py

@@ -10,8 +10,11 @@ that don't scale down to a smaller panel.
 
 Limitations (documented on purpose):
 - Overflow past the LEFT or TOP edge (negative coordinates) is still clipped by
-  PIL and not detected here. The dominant real-world breakage is content that is
-  too wide/tall for a smaller panel, which this catches.
+  PIL and not detected pixel-wise here. The dominant real-world breakage is
+  content that is too wide/tall for a smaller panel, which this catches.
+  As a partial net, draw_text/draw_image calls made with negative coordinates
+  through this manager are recorded in `negative_coordinate_calls` — but draws
+  made directly on the raw PIL canvas remain uncovered.
 - BDF text is clipped to the declared bounds by the parent's bitmap drawer, so
   BDF overflow is not flagged. Golden-image regression covers those plugins.
 - If a plugin replaces the canvas with its own image (display_manager.image = ...),
@@ -56,6 +59,21 @@ class BoundsCheckingDisplayManager(VisualTestDisplayManager):
         super().__init__(self._canvas_width, self._canvas_height)
         # Plugins must see the DECLARED size, not the padded canvas size.
         self.matrix = _MatrixProxy(self._declared_width, self._declared_height)
+        # (text-or-'image', x, y) for every mediated draw call given a
+        # negative coordinate — PIL clips these silently, so record them.
+        self.negative_coordinate_calls: list = []
+
+    # -- negative-coordinate (left/top overflow) recording --
+
+    def draw_text(self, text, x=None, y=None, *args, **kwargs):
+        if (x is not None and x < 0) or (y is not None and y < 0):
+            self.negative_coordinate_calls.append((text, x, y))
+        return super().draw_text(text, x, y, *args, **kwargs)
+
+    def draw_image(self, image, x, y, *args, **kwargs):
+        if x < 0 or y < 0:
+            self.negative_coordinate_calls.append(('image', x, y))
+        return super().draw_image(image, x, y, *args, **kwargs)
 
     # -- declared dimensions (override parent's image-derived properties) --
 

src/plugin_system/testing/harness.py

@@ -73,6 +73,10 @@ class RenderResult:
     golden_ok: Optional[bool] = None
     golden_diff_pixels: int = 0
     golden_max_delta: int = 0
+    # fill / scale-up check (populated only for sizes >= 2x the design size)
+    fill_checked: bool = False
+    fill_ok: Optional[bool] = None       # False only in strict mode
+    fill_extent: Optional[Tuple[float, float]] = None  # (extent_x, extent_y)
 
     @property
     def size_label(self) -> str:
@@ -86,6 +90,8 @@ class RenderResult:
             return False
         if self.golden_checked and self.golden_ok is False:
             return False
+        if self.fill_ok is False:
+            return False
         return True
 
 
@@ -301,6 +307,74 @@ def compare_to_goldens(results: List[RenderResult], golden_dir: Path,
     return results
 
 
+# ---------------------------------------------------------------------------
+# Fill / scale-up check
+# ---------------------------------------------------------------------------
+#
+# Overflow catches content that is too BIG for a panel; nothing catches
+# content that stays tiny on a panel much larger than the plugin's design
+# size (e.g. 128x32 content in the corner of a 256x128 renders "green").
+# These helpers measure how much of the panel the lit content spans so the
+# harness can flag plugins that don't scale up.
+
+# A pixel counts as "lit" above this luminance — low enough to catch dim
+# content, high enough to ignore near-black noise.
+_LIT_THRESHOLD = 16
+# Content must span at least this fraction of an axis that is >= 2x the
+# design size. Lenient on purpose: margins are fine, a tiny corner is not.
+_MIN_FILL_EXTENT = 0.5
+
+
+def fill_metrics(image: Image.Image) -> Tuple[float, float, float]:
+    """Measure lit-content coverage: (extent_x, extent_y, ink_ratio).
+
+    extent_* are the lit bounding box's spans as fractions of the panel;
+    ink_ratio is the fraction of pixels lit (reporting only — sparse pixel
+    fonts legitimately have low ink ratios)."""
+    lit = image.convert("L").point(lambda p: 255 if p > _LIT_THRESHOLD else 0)
+    bbox = lit.getbbox()
+    if bbox is None:
+        return (0.0, 0.0, 0.0)
+    extent_x = (bbox[2] - bbox[0]) / image.width
+    extent_y = (bbox[3] - bbox[1]) / image.height
+    ink = sum(1 for p in lit.getdata() if p) / (image.width * image.height)
+    return (extent_x, extent_y, ink)
+
+
+def check_scale_up(results: List[RenderResult],
+                   design_size: Tuple[int, int] = (128, 32),
+                   min_extent: float = _MIN_FILL_EXTENT,
+                   strict: bool = False) -> List[RenderResult]:
+    """Flag renders that leave a big panel mostly empty.
+
+    For each result whose panel is at least 2x the design size on an axis,
+    require the lit content to span >= min_extent of that axis. Mutates the
+    results' fill_* fields. In the default warn-only mode fill_ok is left
+    None (reported, never failing); strict=True sets fill_ok=False, which
+    fails RenderResult.ok — opt in per plugin via harness.json
+    {"fill_check": "strict"} once its adaptive layout is in place.
+    """
+    design_w, design_h = design_size
+    for r in results:
+        if r.image is None or r.error is not None:
+            continue
+        check_x = r.width >= 2 * design_w
+        check_y = r.height >= 2 * design_h
+        if not (check_x or check_y):
+            continue
+        extent_x, extent_y, _ink = fill_metrics(r.image)
+        r.fill_checked = True
+        r.fill_extent = (round(extent_x, 3), round(extent_y, 3))
+        underfilled = ((check_x and extent_x < min_extent)
+                       or (check_y and extent_y < min_extent))
+        if underfilled and strict:
+            r.fill_ok = False
+        elif not underfilled:
+            r.fill_ok = True
+        # warn-only underfill: fill_ok stays None; fill_extent tells the story
+    return results
+
+
 def write_goldens(results: List[RenderResult], golden_dir: Path) -> int:
     """Write each successfully-rendered result to its golden path. Returns count."""
     written = 0

src/plugin_system/testing/loading.py

@@ -56,7 +56,15 @@ def load_harness_spec(plugin_dir: Union[str, Path]) -> Dict[str, Any]:
           "config":     {...},            # config overrides
           "mock_data":  "fixtures/mock.json",  # path (relative to plugin dir) to cache fixtures
           "freeze_time": "2025-08-01 15:25:00",
-          "skip_update": false
+          "skip_update": false,
+          "fill_check": "warn",           # or "strict": underfilled big panels FAIL
+          "variants": [                   # extra runs with config overlays and
+            {                             # their own golden dirs — e.g. an
+              "name": "adaptive",         # opt-in adaptive mode tested beside
+              "config": {"layout_mode": "adaptive"},   # the classic default
+              "golden_dir": "test/golden-adaptive"
+            }
+          ]
         }
     Returns {} when no harness.json exists.
     """
@@ -80,3 +88,27 @@ def load_harness_spec(plugin_dir: Union[str, Path]) -> Dict[str, Any]:
         with open(mock_path, 'r') as mf:
             spec['mock_data_contents'] = json.load(mf)
     return spec
+
+
+def build_full_config(
+    plugin_dir: Union[str, Path],
+    spec: Optional[Dict[str, Any]] = None,
+    cli_config: Optional[Dict[str, Any]] = None,
+) -> Dict[str, Any]:
+    """Build the config a plugin sees under test.
+
+    Merge order: config_schema.json defaults, then a forced ``enabled: True``,
+    then harness.json's config overlay, then the caller's explicit config --
+    most specific wins. `enabled` is re-asserted *after* the schema defaults
+    so a plugin that reasonably ships `enabled: false` (e.g. a seasonal or
+    opt-in plugin) can't silently make every harness run test "disabled, do
+    nothing" by accident -- callers that genuinely want to test the disabled
+    path can still do so via `cli_config={"enabled": False}`.
+    """
+    spec = spec or {}
+    config: Dict[str, Any] = {}
+    config.update(load_config_defaults(plugin_dir))
+    config["enabled"] = True
+    config.update(spec.get("config", {}))
+    config.update(cli_config or {})
+    return config

src/plugin_system/testing/mocks.py

@@ -71,6 +71,7 @@ class MockCacheManager:
         self.get_calls = []
         self.set_calls = []
         self.delete_calls = []
+        self.get_cached_data_with_strategy_calls = []
         # Real temp dir for plugins that write/read files under cache_dir.
         # Registered for cleanup so each mock instance doesn't leak a tmp dir.
         self.cache_dir = tempfile.mkdtemp(prefix="ledmatrix-mock-cache-")
@@ -108,6 +109,24 @@ class MockCacheManager:
         self.delete_calls.append(key)
         if key in self._cache:
             del self._cache[key]
+
+    def get_cached_data_with_strategy(self, key: str, data_type: str = 'default') -> Optional[Any]:
+        """Mock of CacheManager.get_cached_data_with_strategy (src/cache_manager.py).
+
+        The real method picks a max_age/memory_ttl strategy per data_type
+        (and extends it during market-closed hours for market data) before
+        delegating to get_cached_data(). None of that timing nuance matters
+        for a mock -- plugins under test just need the method to exist and
+        return whatever was cached, so this delegates straight to get().
+        """
+        self.get_cached_data_with_strategy_calls.append({'key': key, 'data_type': data_type})
+        return self.get(key)
+
+    def save_cache(self, key: str, data: Any) -> None:
+        """Mock of CacheManager.save_cache (src/cache_manager.py) -- the
+        write-side counterpart to get_cached_data_with_strategy, used by the
+        same real-CacheManager-oriented plugins. Delegates to set()."""
+        self.set(key, data)
         if key in self._cache_timestamps:
             del self._cache_timestamps[key]
     
@@ -118,6 +137,7 @@ class MockCacheManager:
         self.get_calls = []
         self.set_calls = []
         self.delete_calls = []
+        self.get_cached_data_with_strategy_calls = []
 
 
 class MockConfigManager:
@@ -161,6 +181,13 @@ class MockPluginManager:
         self.plugin_manifests: Dict[str, Dict] = {}
         self.get_plugin_calls = []
         self.get_all_plugins_calls = []
+        # Real FontManager so BasePlugin.layout / draw_fit behave identically
+        # under the harness (it only needs assets/fonts on disk).
+        try:
+            from src.font_manager import FontManager
+            self.font_manager: Optional[Any] = FontManager({})
+        except Exception:
+            self.font_manager = None
     
     def get_plugin(self, plugin_id: str) -> Optional[Any]:
         """Get a plugin instance."""

src/plugin_system/testing/sizes.py

@@ -28,6 +28,7 @@ DEFAULT_TEST_SIZES: List[Tuple[int, int]] = [
     (64, 32),    # 1x1 — single panel, the tightest common rectangle
     (128, 32),   # 2x1 — the baseline most plugins are tuned for
     (64, 64),    # 1x2 — stacked, exercises tall-narrow centering
+    (96, 48),    # non-64x32-module panel (e.g. Waveshare), off-grid dims
     (128, 64),   # 2x2 — block, icon scaling / vertical centering
     (256, 32),   # 4x1 — long strip, wide horizontal layout
     (128, 96),   # 2x3 — tall, exercises vertical overflow

src/plugin_system/testing/visual_display_manager.py

@@ -454,6 +454,18 @@ class VisualTestDisplayManager:
         """Check if display is currently scrolling."""
         return self._scrolling_state['is_scrolling']
 
+    def process_deferred_updates(self):
+        """Process any deferred updates (no-op for testing).
+
+        Several ticker-style plugins (news, odds-ticker, leaderboard,
+        stock-news, stocks) call this unconditionally between
+        set_scrolling_state() and their scroll-position update, mirroring the
+        real display_manager's deferred-update queue. This double has no such
+        queue, so there is nothing to process — the no-op just lets those
+        plugins render under the harness instead of raising AttributeError.
+        """
+        pass
+
     # ------------------------------------------------------------------
     # Utility methods
     # ------------------------------------------------------------------

src/vegas_mode/plugin_adapter.py

@@ -279,6 +279,19 @@ class PluginAdapter:
             # Copy the image to prevent modification
             img = cached_image.copy()
 
+            # Plugins that build their own ticker image via this shared
+            # ScrollHelper's create_scrolling_image() get a solid-black
+            # leading margin exactly `display_width` columns wide baked in
+            # (scroll_helper.py's "initial gap before first item"). Vegas mode
+            # adds its own leading gap/separator around every item already,
+            # so leaving this in stacks a second, uncontrolled blank margin on
+            # top of vegas_scroll.separator_width — making this plugin's
+            # transitions look inconsistent with plugins that provide content
+            # via get_vegas_content() (which carries no such margin). Strip it
+            # here so every plugin contributes only its real content and the
+            # gap between items is governed solely by separator_width.
+            img = self._strip_scroll_padding(img, scroll_helper, plugin_id)
+
             # Ensure correct height
             if img.height != self.display_height:
                 logger.info(
@@ -306,6 +319,69 @@ class PluginAdapter:
             logger.exception("[%s] Error getting scroll_helper content", plugin_id)
             return None
 
+    def _strip_scroll_padding(
+        self, img: Image.Image, scroll_helper: Any, plugin_id: str
+    ) -> Image.Image:
+        """
+        Crop off a plugin's own leading/trailing blank margins, if present.
+
+        create_scrolling_image() always pads the *start* of its cached image
+        with exactly `scroll_helper.display_width` columns of solid black
+        (0, 0, 0) ("initial gap before first item"). Some ticker-style plugins
+        also pad the *end* of their own cached image (e.g. so their standalone
+        display exits cleanly before looping). Vegas mode already adds its own
+        gap/separator around every item, so either margin left in place stacks
+        an extra, uncontrolled blank stretch on top of `separator_width` —
+        only when running inside Vegas mode does this matter, since the
+        plugin's own standalone display still wants that margin. Detect solid
+        black margins up to `scroll_helper.display_width` wide on each edge and
+        crop them here. Images built via set_scrolling_image() (no such
+        margins) are left untouched.
+
+        Args:
+            img: Captured scroll_helper.cached_image (already copied)
+            scroll_helper: The plugin's ScrollHelper instance
+            plugin_id: Plugin identifier for logging
+
+        Returns:
+            img, cropped on whichever edge(s) had a matching blank margin
+        """
+        pad_width = getattr(scroll_helper, 'display_width', None)
+        if not isinstance(pad_width, int) or pad_width <= 0 or pad_width >= img.width:
+            return img
+
+        def is_solid_black(strip: Image.Image) -> bool:
+            return strip.convert('RGB').getextrema() == ((0, 0), (0, 0), (0, 0))
+
+        left = pad_width if is_solid_black(img.crop((0, 0, pad_width, img.height))) else 0
+        right = (
+            pad_width
+            if is_solid_black(img.crop((img.width - pad_width, 0, img.width, img.height)))
+            else 0
+        )
+
+        if not left and not right:
+            return img
+
+        # Degenerate case (e.g. an all-black cached image): don't crop past
+        # zero width, just leave the image as-is.
+        if left + right >= img.width:
+            return img
+
+        cropped = img.crop((left, 0, img.width - right, img.height))
+
+        # Both edges matching at once is a much stronger signal of genuine
+        # baked-in padding than a single edge (which has a small chance of
+        # coinciding with real all-black content, e.g. a dark logo touching
+        # one boundary). Log that case at warning level so an unexpected
+        # double-edge crop is easy to spot in the field.
+        log = logger.warning if (left and right) else logger.info
+        log(
+            "[%s] Stripping scroll_helper padding (left=%dpx, right=%dpx): %dpx -> %dpx",
+            plugin_id, left, right, img.width, cropped.width
+        )
+        return cropped
+
     def _trigger_scroll_content_generation(
         self, plugin: 'BasePlugin', plugin_id: str, scroll_helper: Any
     ) -> Optional[Image.Image]:

src/vegas_mode/render_pipeline.py

@@ -66,6 +66,10 @@ class RenderPipeline:
             else display_manager.height
         )
 
+        # Reusable blank frame for cycle-end pushes (allocated lazily,
+        # re-blacked before each reuse)
+        self._blank_frame = None
+
         # ScrollHelper for optimized scrolling
         self.scroll_helper = ScrollHelper(
             self.display_width,
@@ -234,11 +238,19 @@ class RenderPipeline:
                     )
                     # Push blank immediately so the hardware never shows any
                     # post-wrap content while the coordinator recomposes the
-                    # next cycle (~100 ms).
+                    # next cycle (~100 ms). The blank is allocated once and
+                    # reused across cycle wraps (fresh paste each time in case
+                    # a consumer drew on the previous one).
                     try:
-                        from PIL import Image as _Image
-                        blank = _Image.new('RGB', (self.display_width, self.display_height))
-                        self.display_manager.image = blank
+                        if self._blank_frame is None or self._blank_frame.size != (
+                                self.display_width, self.display_height):
+                            self._blank_frame = Image.new(
+                                'RGB', (self.display_width, self.display_height))
+                        else:
+                            self._blank_frame.paste(
+                                (0, 0, 0),
+                                (0, 0, self.display_width, self.display_height))
+                        self.display_manager.image = self._blank_frame
                         self.display_manager.update_display()
                     except Exception:
                         logger.exception("Failed to write blank frame to display at cycle end")
@@ -297,6 +309,8 @@ class RenderPipeline:
         Returns True when:
         - Cycle is complete and we should start fresh
         - Staging buffer has new content
+        - A plugin currently visible in the scroll has pending updated data
+          (e.g. a live score changed) — standalone (non-sync) mode only
         """
         if self._cycle_complete:
             return True
@@ -314,6 +328,12 @@ class RenderPipeline:
         if buffer_status['staging_count'] > 0:
             return True
 
+        # Trigger recompose when pending updates affect visible segments, so
+        # live score/status changes reach the display within a few seconds
+        # instead of waiting for the next full cycle.
+        if self.stream_manager.has_pending_updates_for_visible_segments():
+            return True
+
         return False
 
     def hot_swap_content(self) -> bool:

src/wifi_manager.py

@@ -1883,7 +1883,96 @@ class WiFiManager:
         
         logger.warning(f"Failed to enable WiFi radio after {max_retries} attempts")
         return False
-    
+
+    def get_wifi_radio_state(self) -> Dict:
+        """
+        Report whether the WiFi radio is currently enabled, plus whether a wired
+        fallback exists. Used by the web UI's radio toggle so it can warn before
+        an action that could disconnect the browser.
+
+        Returns:
+            {
+                'enabled': Optional[bool],   # True/False, or None if undeterminable
+                'ethernet_connected': bool,  # wired fallback present
+                'available': bool,           # nmcli present / radio state readable
+            }
+        """
+        ethernet_connected = self._is_ethernet_connected()
+        enabled: Optional[bool] = None
+        available = False
+        try:
+            result = subprocess.run(
+                ["nmcli", "radio", "wifi"],
+                capture_output=True,
+                text=True,
+                timeout=5
+            )
+            if result.returncode == 0:
+                status = result.stdout.strip().lower()
+                if status in ("enabled", "disabled"):
+                    enabled = status == "enabled"
+                    available = True
+        except Exception as e:
+            logger.debug(f"Could not read WiFi radio state: {e}")
+        return {
+            'enabled': enabled,
+            'ethernet_connected': ethernet_connected,
+            'available': available,
+        }
+
+    def set_wifi_radio(self, enabled: bool, force: bool = False) -> Tuple[bool, str, Optional[str]]:
+        """
+        Turn the WiFi radio on or off.
+
+        Turning the radio OFF from the web interface is dangerous: if the device
+        is reachable only over WiFi, disabling it disconnects the very page that
+        issued the request. To prevent that lockout, disabling is refused unless a
+        wired (Ethernet) fallback is present, or the caller explicitly passes
+        force=True to acknowledge the risk.
+
+        Enabling reuses the hardened _ensure_wifi_radio_enabled() path (handles
+        rfkill soft-blocks + retries). Both directions rely only on
+        `nmcli radio wifi on|off`, which is already covered by the passwordless
+        sudoers allowlist (configure_wifi_permissions.sh) — no new privileged
+        command is introduced.
+
+        Returns:
+            (success, human-readable message, reason_code). reason_code is
+            'no_ethernet' when a disable is refused for lockout safety, or a
+            short failure code otherwise; None on success. The web UI keys on
+            'no_ethernet' to decide whether to offer a force-off prompt.
+        """
+        if enabled:
+            if self._ensure_wifi_radio_enabled():
+                return True, "WiFi radio enabled.", None
+            return False, "Failed to enable WiFi radio. Check logs for details.", 'enable_failed'
+
+        # Disabling — guard against locking the user out of the web interface.
+        if not force and not self._is_ethernet_connected():
+            return False, (
+                "Refusing to disable WiFi: no wired (Ethernet) connection was "
+                "detected, so turning off WiFi would disconnect you from this "
+                "page. Connect Ethernet first, or force it if you're sure."
+            ), 'no_ethernet'
+
+        try:
+            result = subprocess.run(
+                ["sudo", "nmcli", "radio", "wifi", "off"],
+                capture_output=True,
+                text=True,
+                timeout=10
+            )
+            if result.returncode == 0:
+                logger.info("WiFi radio disabled via web interface (force=%s)", force)
+                return True, "WiFi radio disabled.", None
+            logger.warning("Failed to disable WiFi radio: %s", result.stderr.strip())
+            return False, "Failed to disable WiFi radio. Check logs for details.", 'command_failed'
+        except subprocess.TimeoutExpired:
+            return False, "Command timed out while disabling WiFi radio.", 'timeout'
+        except (OSError, subprocess.SubprocessError) as e:
+            logger.error("Error disabling WiFi radio: %s", e, exc_info=True)
+            return False, "An error occurred while disabling WiFi radio.", 'error'
+
     def enable_ap_mode(self, force: bool = False) -> Tuple[bool, str]:
         """
         Enable access point mode
@@ -2475,11 +2564,35 @@ address=/detectportal.firefox.com/192.168.4.1
         Returns:
             True if AP mode state changed, False otherwise
         """
+        changed, _status, _ethernet, _ap = self.check_and_manage_ap_mode_with_state()
+        return changed
+
+    def check_and_manage_ap_mode_with_state(self) -> Tuple[bool, WiFiStatus, bool, bool]:
+        """Like check_and_manage_ap_mode, but also returns the state it
+        observed, so callers (the wifi monitor daemon) don't have to re-run
+        the same nmcli subprocess battery before AND after the check —
+        each status fetch is several process forks.
+
+        Returns:
+            (state_changed, WiFiStatus, ethernet_connected, ap_active_after)
+        """
         try:
             # Get status with retry for more reliable detection
             status = self._get_wifi_status_with_retry()
             ethernet_connected = self._is_ethernet_connected()
             ap_active = self._is_ap_mode_active()
+            changed = self._manage_ap_mode(status, ethernet_connected, ap_active)
+            # State only ever changes via one enable or one disable, so the
+            # post-state is the inverse of the pre-state when changed.
+            ap_after = (not ap_active) if changed else ap_active
+            return changed, status, ethernet_connected, ap_after
+        except Exception as e:
+            logger.error(f"Error checking AP mode: {e}", exc_info=True)
+            return False, WiFiStatus(connected=False), False, False
+
+    def _manage_ap_mode(self, status: WiFiStatus, ethernet_connected: bool, ap_active: bool) -> bool:
+        """AP-mode decision logic against an already-fetched state snapshot."""
+        try:
             auto_enable = self.config.get("auto_enable_ap_mode", True)  # Default: True (safe due to grace period)
             
             # Log current state for debugging

test/conftest.py

@@ -38,7 +38,11 @@ def mock_cache_manager():
     mock._memory_cache_timestamps = {}
     mock.cache_dir = "/tmp/test_cache"
     
-    def mock_get(key: str, max_age: int = 300) -> Optional[Dict]:
+    def mock_get(key: str, max_age: Optional[int] = 300,
+                 memory_ttl: Optional[int] = None) -> Optional[Dict]:
+        # Signature mirrors CacheManager.get — keep in sync or callers
+        # passing keyword args (health tracker, resource monitor) break
+        # only in tests, hiding real-API compatibility.
         return mock._memory_cache.get(key)
     
     def mock_set(key: str, data: Dict, ttl: Optional[int] = None) -> None:

test/plugins/test_harness.py

@@ -253,3 +253,61 @@ class TestCheckPluginHonorsHarnessJson:
         )
         assert captured["freeze_time"] == "2030-01-01 00:00:00"
         assert captured["config"]["timezone"] == "America/New_York"
+
+
+class TestBuildFullConfigForcesEnabled:
+    """Regression: a plugin's own config_schema.json may reasonably default
+    enabled to False (e.g. a seasonal or opt-in plugin) -- march-madness and
+    14 other real plugins do. The harness must still test it as enabled
+    unless a caller explicitly asks otherwise, or every render silently
+    becomes a same-shaped "disabled, do nothing" no-op."""
+
+    def _make_plugin_with_disabled_default(self, tmp_path):
+        pdir = tmp_path / "plugins" / "demo-seasonal"
+        pdir.mkdir(parents=True)
+        (pdir / "manifest.json").write_text(json.dumps({
+            "id": "demo-seasonal", "name": "Demo Seasonal", "version": "1.0.0",
+            "author": "test", "entry_point": "manager.py",
+            "class_name": "DemoSeasonal", "display_modes": ["demo-seasonal"],
+            "compatible_versions": ["*"],
+        }))
+        (pdir / "config_schema.json").write_text(json.dumps({
+            "type": "object",
+            "properties": {"enabled": {"type": "boolean", "default": False}},
+        }))
+        return pdir
+
+    def test_schema_disabled_default_does_not_win(self, tmp_path):
+        from src.plugin_system.testing.loading import build_full_config
+        plugin_dir = self._make_plugin_with_disabled_default(tmp_path)
+        config = build_full_config(plugin_dir)
+        assert config["enabled"] is True
+
+    def test_harness_json_config_can_still_disable(self, tmp_path):
+        from src.plugin_system.testing.loading import build_full_config
+        plugin_dir = self._make_plugin_with_disabled_default(tmp_path)
+        config = build_full_config(plugin_dir, spec={"config": {"enabled": False}})
+        assert config["enabled"] is False
+
+    def test_explicit_cli_config_can_still_disable(self, tmp_path):
+        from src.plugin_system.testing.loading import build_full_config
+        plugin_dir = self._make_plugin_with_disabled_default(tmp_path)
+        config = build_full_config(plugin_dir, cli_config={"enabled": False})
+        assert config["enabled"] is False
+
+    def test_check_one_renders_a_schema_disabled_plugin_as_enabled(self, tmp_path, monkeypatch):
+        """End-to-end: check_plugin.py's check_one() must not blank-render a
+        plugin just because its own schema defaults enabled to False."""
+        mod = _load_check_plugin_cli()
+        plugin_dir = self._make_plugin_with_disabled_default(tmp_path)
+        captured = {}
+        monkeypatch.setattr(mod, "render_plugin_matrix",
+                            lambda **kw: captured.update(kw) or [])
+        monkeypatch.setattr(mod, "compare_to_goldens", lambda *a, **k: [])
+        mod.check_one(
+            plugin_id="demo-seasonal", search_dirs=[str(tmp_path / "plugins")],
+            sizes=None, mock_data={}, config={}, run_update=True,
+            out_dir=None, update_golden=False, golden_dir_override=None,
+            freeze_time=None,
+        )
+        assert captured["config"]["enabled"] is True

test/plugins/test_plugin_matrix.py

@@ -22,7 +22,7 @@ import pytest
 from src.plugin_system.testing.harness import (
     render_plugin_matrix, compare_to_goldens,
 )
-from src.plugin_system.testing.loading import load_config_defaults, load_harness_spec
+from src.plugin_system.testing.loading import build_full_config, load_harness_spec
 from src.plugin_system.testing.sizes import resolve_test_sizes
 
 PROJECT_ROOT = Path(__file__).resolve().parents[2]
@@ -81,9 +81,7 @@ def test_plugin_renders_across_sizes_and_screens(plugin_id: str) -> None:
     plugin_dir = _PLUGINS[plugin_id]
     spec = load_harness_spec(plugin_dir)
 
-    config = {"enabled": True}
-    config.update(load_config_defaults(plugin_dir))
-    config.update(spec.get("config", {}))
+    config = build_full_config(plugin_dir, spec)
 
     # Sizes: LEDMATRIX_TEST_SIZES env (test on real hardware) wins, then the
     # plugin's own harness.json "sizes", else the default representative sample.

test/plugins/test_visual_rendering.py

@@ -172,6 +172,16 @@ class TestVisualDisplayManager:
         vdm.set_scrolling_state(False)
         assert vdm.is_currently_scrolling() is False
 
+    def test_process_deferred_updates_is_noop(self):
+        # Ticker-style plugins (news, odds-ticker, leaderboard, stock-news,
+        # stocks) call this unconditionally alongside set_scrolling_state();
+        # it must exist and be harmless so those plugins render under the
+        # harness instead of raising AttributeError.
+        vdm = VisualTestDisplayManager(width=128, height=32)
+        vdm.set_scrolling_state(True)
+        vdm.process_deferred_updates()  # should not raise
+        assert vdm.is_currently_scrolling() is True
+
     def test_format_date_with_ordinal(self):
         from datetime import datetime
         vdm = VisualTestDisplayManager(width=128, height=32)

test/test_adaptive_images.py

@@ -0,0 +1,208 @@
+"""Tests for adaptive image fitting (src/adaptive_images.py) and the
+LayoutContext image cache."""
+
+import pytest
+from PIL import Image
+
+from src.adaptive_images import (
+    RESAMPLE_LANCZOS,
+    RESAMPLE_NEAREST,
+    ImageFitResult,
+    draw_fitted_image,
+    fit_image,
+)
+from src.adaptive_layout import LayoutContext, Region
+from src.font_manager import FontManager
+
+
+@pytest.fixture(scope="module")
+def font_manager():
+    return FontManager({})
+
+
+@pytest.fixture
+def ctx(font_manager):
+    return LayoutContext(128, 32, font_manager)
+
+
+def _solid(w, h, color=(255, 0, 0, 255)):
+    return Image.new("RGBA", (w, h), color)
+
+
+def _padded_logo(ink_w=10, ink_h=10, pad=10):
+    """Transparent canvas with a solid ink block in the middle — models a
+    logo shipped with generous transparent padding."""
+    img = Image.new("RGBA", (ink_w + 2 * pad, ink_h + 2 * pad), (0, 0, 0, 0))
+    img.paste(_solid(ink_w, ink_h), (pad, pad))
+    return img
+
+
+class TestFitModes:
+    def test_contain_letterboxes_and_upscales(self):
+        fit = fit_image(_solid(10, 5), (40, 40))
+        assert (fit.width, fit.height) == (40, 20)  # aspect preserved
+        assert fit.scale == 4.0
+
+    def test_contain_no_upscale(self):
+        fit = fit_image(_solid(10, 5), (40, 40), upscale=False)
+        assert (fit.width, fit.height) == (10, 5)
+        assert fit.scale == 1.0
+
+    def test_cover_fills_and_crops(self):
+        fit = fit_image(_solid(10, 20), (40, 40), mode="cover")
+        assert (fit.width, fit.height) == (40, 40)
+
+    def test_cover_top_anchor(self):
+        # top half red, bottom half blue; cover-crop a wide box with top anchor
+        img = Image.new("RGBA", (20, 40), (0, 0, 255, 255))
+        img.paste(_solid(20, 20, (255, 0, 0, 255)), (0, 0))
+        fit = fit_image(img, (20, 20), mode="cover", anchor="top")
+        assert fit.image.getpixel((10, 5))[:3] == (255, 0, 0)  # kept the top
+
+    def test_fill_height_matches_box_height(self):
+        fit = fit_image(_solid(10, 10), (64, 32), mode="fill_height")
+        assert fit.height == 32 and fit.width == 32
+
+    def test_fill_height_capped_by_width(self):
+        # very wide source: height-fill would overflow the box width
+        fit = fit_image(_solid(100, 10), (40, 32), mode="fill_height")
+        assert fit.width <= 40
+
+    def test_stretch_exact(self):
+        fit = fit_image(_solid(3, 7), (25, 13), mode="stretch")
+        assert (fit.width, fit.height) == (25, 13)
+
+    def test_crop_to_ink(self):
+        fit = fit_image(_padded_logo(), (30, 30), crop_to_ink=True)
+        # 10x10 ink upscaled to fill 30x30 (padding would have kept it small)
+        assert (fit.width, fit.height) == (30, 30)
+        no_crop = fit_image(_padded_logo(), (30, 30), crop_to_ink=False)
+        assert no_crop.width == 30  # whole padded canvas scaled instead
+
+    def test_fully_transparent_source(self):
+        img = Image.new("RGBA", (10, 10), (0, 0, 0, 0))
+        fit = fit_image(img, (20, 20), crop_to_ink=True)
+        assert fit.is_empty
+
+    def test_degenerate_box(self):
+        assert fit_image(_solid(10, 10), (0, 20)).is_empty
+        assert fit_image(_solid(10, 10), Region(0, 0, 20, 0)).is_empty
+
+    def test_output_always_rgba(self):
+        rgb = Image.new("RGB", (10, 10), (1, 2, 3))
+        assert fit_image(rgb, (20, 20)).image.mode == "RGBA"
+
+    def test_nearest_keeps_hard_edges(self):
+        # 2x2 checker scaled 8x: NEAREST keeps pure colors, LANCZOS blends
+        img = Image.new("RGBA", (2, 2), (0, 0, 0, 255))
+        img.putpixel((0, 0), (255, 255, 255, 255))
+        near = fit_image(img, (16, 16), mode="stretch", resample=RESAMPLE_NEAREST)
+        colors = {near.image.getpixel((x, y))[:3] for x in range(16) for y in range(16)}
+        assert colors == {(255, 255, 255), (0, 0, 0)}
+
+    def test_unknown_mode_raises(self):
+        with pytest.raises(ValueError):
+            fit_image(_solid(4, 4), (8, 8), mode="tile")
+
+
+class TestDrawFittedImage:
+    class _DM:
+        def __init__(self, w=64, h=32):
+            self.image = Image.new("RGB", (w, h), (0, 0, 0))
+
+    def test_pastes_aligned_in_region(self):
+        dm = self._DM()
+        box = Region(10, 4, 20, 20)
+        fit = fit_image(_solid(10, 10), box)
+        xy = draw_fitted_image(dm, fit, box)
+        assert xy == box.align_xy(fit.width, fit.height)
+        assert dm.image.getpixel((xy[0] + 1, xy[1] + 1)) == (255, 0, 0)
+
+    def test_offset_translates(self):
+        dm = self._DM()
+        box = Region(0, 0, 20, 20)
+        fit = fit_image(_solid(10, 10), box)
+        x, y = draw_fitted_image(dm, fit, box, align="left", valign="top",
+                                 offset=(3, 5))
+        assert (x, y) == (3, 5)
+
+    def test_empty_fit_noops(self):
+        dm = self._DM()
+        fit = fit_image(_solid(10, 10), (0, 0))
+        assert draw_fitted_image(dm, fit, Region(0, 0, 10, 10)) is None
+
+
+class TestContextImageCache:
+    def test_size_keyed_hit_and_miss(self, ctx):
+        img = _solid(10, 10)
+        a = ctx.fit_image(img, (20, 20), cache_key="logo:A")
+        assert ctx.fit_image(img, (20, 20), cache_key="logo:A") is a
+        b = ctx.fit_image(img, (30, 30), cache_key="logo:A")
+        assert b is not a and b.width == 30  # different box size = new entry
+
+    def test_id_keyed_default(self, ctx):
+        img = _solid(10, 10)
+        a = ctx.fit_image(img, (20, 20))
+        assert ctx.fit_image(img, (20, 20)) is a
+
+    def test_id_safety_pins_source(self, ctx):
+        # id()-keyed entries must pin the source image so a recycled id
+        # can't alias a dead image's cache entry.
+        img = _solid(10, 10)
+        ctx.fit_image(img, (20, 20))
+        pinned = [entry[1] for entry in ctx._image_cache.values()]
+        assert img in pinned
+
+    def test_cache_key_entries_do_not_pin(self, ctx):
+        img = _solid(10, 10)
+        ctx.fit_image(img, (20, 20), cache_key="logo:X")
+        key = next(k for k in ctx._image_cache if k[1] == "logo:X")
+        assert ctx._image_cache[key][1] is None
+
+    def test_lru_eviction(self, ctx):
+        for i in range(ctx._IMAGE_CACHE_MAX + 5):
+            ctx.fit_image(_solid(4, 4), (8, 8), cache_key=f"k{i}")
+        assert len(ctx._image_cache) == ctx._IMAGE_CACHE_MAX
+        assert not any(k[1] == "k0" for k in ctx._image_cache)  # oldest evicted
+
+    def test_clear_cache_clears_images(self, ctx):
+        ctx.fit_image(_solid(4, 4), (8, 8), cache_key="k")
+        ctx.clear_cache()
+        assert len(ctx._image_cache) == 0
+
+
+class TestBasePluginDrawImage:
+    def test_draw_image_end_to_end(self):
+        from src.plugin_system.base_plugin import BasePlugin
+        from src.plugin_system.testing.mocks import (
+            MockCacheManager, MockDisplayManager, MockPluginManager,
+        )
+
+        class _P(BasePlugin):
+            def update(self):
+                pass
+
+            def display(self, force_clear=False):
+                pass
+
+        plugin = _P("t", {}, MockDisplayManager(64, 32),
+                    MockCacheManager(), MockPluginManager())
+        logo = _padded_logo()
+        box = plugin.layout.bounds.left_col(32)
+        ifit = plugin.draw_image(logo, box, mode="fill_height",
+                                 crop_to_ink=True, cache_key="logo:T")
+        assert ifit.height == 32
+        # pasted onto the mock's canvas
+        assert plugin.display_manager.image.getpixel((16, 16)) != (0, 0, 0)
+
+
+class TestResultIndependence:
+    def test_same_size_fit_never_aliases_the_source(self):
+        """LayoutContext caches ImageFitResults — an aliased image would let
+        later mutations of the source corrupt cached fits (or vice versa)."""
+        from PIL import ImageDraw
+        src = Image.new("RGBA", (20, 20), (255, 0, 0, 255))
+        fit = fit_image(src, (20, 20))
+        assert fit.image is not src
+        ImageDraw.Draw(src).rectangle([0, 0, 19, 19], fill=(0, 255, 0, 255))
+        assert fit.image.getpixel((5, 5)) == (255, 0, 0, 255)

test/test_adaptive_layout.py

@@ -0,0 +1,454 @@
+"""Tests for the adaptive layout system (src/adaptive_layout.py)."""
+
+import pytest
+
+from src.adaptive_layout import (
+    DEFAULT_DESIGN_SIZE,
+    LADDER_ARCADE,
+    LADDER_GRID,
+    LayoutContext,
+    Region,
+    draw_fitted_text,
+    measure_font_crispness,
+    measure_ink,
+    media_row,
+    scoreboard_regions,
+)
+from src.plugin_system.testing.sizes import DEFAULT_TEST_SIZES
+from src.font_manager import FontManager
+
+
+@pytest.fixture(scope="module")
+def font_manager():
+    """Real FontManager over assets/fonts — the ladders depend on it."""
+    return FontManager({})
+
+
+@pytest.fixture
+def ctx(font_manager):
+    return LayoutContext(128, 32, font_manager)
+
+
+class TestRegion:
+    """Pure integer rect algebra."""
+
+    def test_bands_partition_without_overlap(self):
+        r = Region(0, 0, 128, 32)
+        top = r.top_band(7)
+        bottom = r.bottom_band(7)
+        middle = r.middle(7, 7)
+        assert top.bottom == middle.y
+        assert middle.bottom == bottom.y
+        assert top.h + middle.h + bottom.h == r.h
+
+    def test_bands_clamp_on_short_panel(self):
+        # The classic failure: y=1 top band and y=height-7 bottom band
+        # overlapping on a short panel. Bands can't exceed the region.
+        r = Region(0, 0, 32, 8)
+        assert r.top_band(16).h == 8
+        assert r.bottom_band(16).h == 8
+        assert r.middle(8, 8).h == 0  # degenerate, never negative
+
+    def test_split_v_weights_sum_to_height(self):
+        r = Region(0, 0, 64, 33)
+        rows = r.split_v(3, 1, 1, gap=1)
+        assert len(rows) == 3
+        assert sum(row.h for row in rows) == 33 - 2  # two 1px gaps
+        assert rows[0].h > rows[1].h
+        assert rows[-1].bottom == r.bottom
+
+    def test_split_h_columns_advance(self):
+        r = Region(0, 0, 100, 32)
+        cols = r.split_h(1, 1, gap=2)
+        assert cols[0].right + 2 == cols[1].x
+        assert cols[1].right == r.right
+
+    def test_degenerate_sizes_never_negative(self):
+        for w, h in [(8, 8), (32, 16), (1, 1)]:
+            r = Region(0, 0, w, h).inset(4)
+            assert r.w >= 0 and r.h >= 0
+            for sub in r.split_v(1, 1) + r.split_h(1, 1, gap=3):
+                assert sub.w >= 0 and sub.h >= 0
+
+    def test_align_xy(self):
+        r = Region(10, 10, 100, 20)
+        assert r.align_xy(20, 10, "left", "top") == (10, 10)
+        assert r.align_xy(20, 10, "right", "bottom") == (90, 20)
+        assert r.align_xy(20, 10) == (50, 15)
+
+    def test_left_right_cols(self):
+        r = Region(0, 0, 128, 32)
+        assert r.left_col(32) == Region(0, 0, 32, 32)
+        assert r.right_col(32) == Region(96, 0, 32, 32)
+
+    def test_offset_translates_without_resizing(self):
+        r = Region(5, 5, 20, 10).offset(3, -2)
+        assert r == Region(8, 3, 20, 10)
+
+
+class TestScoreboardRegions:
+    @pytest.mark.parametrize("w,h", DEFAULT_TEST_SIZES + [(8, 8)])
+    def test_invariants_at_all_sizes(self, w, h):
+        regs = scoreboard_regions(Region(0, 0, w, h))
+        assert regs.logo_slot <= min(h, w // 2)
+        # slots hug the edges and never overlap the center column
+        assert regs.away_slot.x == 0 and regs.home_slot.right == w
+        assert regs.away_slot.right <= regs.center_col.x or regs.center_col.w == 0
+        assert regs.center_col.right <= regs.home_slot.x or regs.center_col.w == 0
+        # bands stack inside the center column without overlap
+        assert regs.status_band.bottom <= regs.score_area.y or regs.score_area.h == 0
+        assert regs.score_area.bottom <= regs.detail_band.y or regs.score_area.h == 0
+        # everything within bounds, nothing negative
+        for reg in (regs.away_slot, regs.home_slot, regs.center_col,
+                    regs.status_band, regs.score_area, regs.detail_band,
+                    regs.bottom_left, regs.bottom_right):
+            assert reg.w >= 0 and reg.h >= 0
+            assert reg.x >= 0 and reg.y >= 0
+            assert reg.right <= w and reg.bottom <= h
+
+    @pytest.mark.parametrize("w,h", [(96, 48), (128, 64), (256, 128), (64, 32), (128, 96)])
+    def test_2to1_aspect_gets_a_center_reserve(self, w, h):
+        """These sizes are all <= 2:1 aspect, where the raw min(h, w//2)
+        formula claims the entire width for logos and leaves zero pixels
+        for a center column — the bug this reserve exists to fix."""
+        regs = scoreboard_regions(Region(0, 0, w, h))
+        assert regs.center_col.w >= int(w * 0.15) - 1  # -1 for int() rounding
+
+    @pytest.mark.parametrize("w,h", [(128, 32), (192, 48), (256, 32)])
+    def test_wide_panels_unaffected_by_center_reserve(self, w, h):
+        """Wide (>= ~4:1) panels already have height as the tighter
+        constraint, so the center reserve must be a no-op there — the
+        design-size baseline's proportions shouldn't shift."""
+        regs = scoreboard_regions(Region(0, 0, w, h))
+        assert regs.logo_slot == min(h, w // 2)
+
+    def test_center_reserve_fraction_is_configurable(self):
+        # min_center_design_px=0 isolates the fraction term (otherwise the
+        # scaled absolute floor can dominate and mask a fraction change).
+        regs_default = scoreboard_regions(Region(0, 0, 128, 64), min_center_design_px=0)
+        regs_wider = scoreboard_regions(Region(0, 0, 128, 64), min_center_fraction=0.5,
+                                        min_center_design_px=0)
+        assert regs_wider.center_col.w > regs_default.center_col.w
+        assert regs_wider.logo_slot < regs_default.logo_slot
+
+    def test_score_bleed_extends_past_center_col(self):
+        regs = scoreboard_regions(Region(0, 0, 128, 64), score_bleed_fraction=0.5)
+        assert regs.score_area.w > regs.center_col.w
+        assert regs.score_area.x < regs.center_col.x
+        assert regs.score_area.right > regs.center_col.right
+
+    def test_score_bleed_zero_matches_center_col(self):
+        regs = scoreboard_regions(Region(0, 0, 128, 64), score_bleed_fraction=0.0)
+        assert regs.score_area.w == regs.center_col.w
+        assert regs.score_area.x == regs.center_col.x
+
+    @pytest.mark.parametrize("w,h", [(64, 32), (96, 48), (128, 64), (256, 128), (128, 96)])
+    def test_score_never_needs_ellipsis_for_a_short_score(self, w, h, font_manager):
+        """The concrete regression this whole reserve/bleed system exists to
+        prevent: a real game score like '17-21' must always render in full,
+        never truncated, at every 2:1-or-tighter aspect ratio in the sample."""
+        ctx = LayoutContext(w, h, font_manager)
+        regs = scoreboard_regions(Region(0, 0, w, h), ctx=ctx)
+        height_scale = h / 32.0
+        fit = ctx.fit_text_proportional("17-21", regs.score_area, base_size_px=10,
+                                        ladder=LADDER_ARCADE, scale=height_scale)
+        assert fit.text == "17-21"
+        assert fit.fits
+
+    def test_ctx_scales_band_heights(self, font_manager):
+        small = scoreboard_regions(Region(0, 0, 128, 32),
+                                   ctx=LayoutContext(128, 32, font_manager))
+        big = scoreboard_regions(Region(0, 0, 256, 64),
+                                 ctx=LayoutContext(256, 64, font_manager))
+        assert big.status_band.h > small.status_band.h
+
+    def test_works_on_offset_card_region(self):
+        card = Region(10, 4, 100, 24)
+        regs = scoreboard_regions(card)
+        assert regs.away_slot.x == 10
+        assert regs.home_slot.right == card.right
+
+
+class TestMediaRow:
+    def test_square_art_plus_body(self):
+        row = media_row(Region(0, 0, 128, 32))
+        assert row.art == Region(0, 0, 32, 32)
+        assert row.body.x == 32 + 2 and row.body.right == 128
+
+    def test_non_square(self):
+        row = media_row(Region(0, 0, 100, 20), square=False, gap=4)
+        assert row.art.w == 50
+        assert row.body.x == 54
+
+    def test_narrow_panel_clamps(self):
+        row = media_row(Region(0, 0, 16, 32))
+        assert row.art.w == 16 and row.body.w == 0
+
+
+class TestLayoutContext:
+    def test_tiers(self, font_manager):
+        assert LayoutContext(128, 32, font_manager).tier == "sm"
+        assert LayoutContext(96, 48, font_manager).tier == "md"
+        assert LayoutContext(128, 64, font_manager).tier == "lg"
+        assert LayoutContext(64, 16, font_manager).tier == "xs"
+        assert LayoutContext(256, 128, font_manager).tier == "xl"
+
+    def test_wide_short_flag(self, font_manager):
+        assert LayoutContext(128, 32, font_manager).is_wide_short
+        assert not LayoutContext(128, 64, font_manager).is_wide_short
+
+    def test_scale_against_design_size(self, font_manager):
+        assert LayoutContext(128, 32, font_manager).scale == 1.0
+        assert LayoutContext(256, 64, font_manager).scale == 2.0
+        # min() of the two axes: don't overscale the constrained one
+        assert LayoutContext(256, 32, font_manager).scale == 1.0
+        assert DEFAULT_DESIGN_SIZE == (128, 32)
+
+    def test_px_scales_and_clamps(self, font_manager):
+        big = LayoutContext(256, 64, font_manager)
+        assert big.px(4) == 8
+        assert big.px(4, maximum=6) == 6
+        tiny = LayoutContext(32, 16, font_manager)
+        assert tiny.px(4, minimum=2) == 2
+
+    def test_by_tier_nearest_at_or_below(self, font_manager):
+        mapping = {"sm": 10, "lg": 18}
+        assert LayoutContext(128, 32, font_manager).by_tier(mapping) == 10
+        assert LayoutContext(96, 48, font_manager).by_tier(mapping) == 10  # md -> sm
+        assert LayoutContext(128, 64, font_manager).by_tier(mapping) == 18
+        assert LayoutContext(256, 128, font_manager).by_tier(mapping) == 18  # xl -> lg
+        # nothing at-or-below: fall forward to smallest defined above
+        assert LayoutContext(64, 16, font_manager).by_tier(mapping) == 10
+
+
+class TestFontFitting:
+    def test_ladder_monotonic(self, font_manager):
+        """Each ladder rung must render no taller than the one before it."""
+        for ladder in (LADDER_GRID, LADDER_ARCADE):
+            heights = []
+            for step in ladder:
+                font = font_manager.get_font(step.family, step.size_px)
+                heights.append(measure_ink("Ay0", font)[1])
+            assert heights == sorted(heights, reverse=True), (
+                f"ladder not monotonically shrinking: {heights}")
+
+    def test_ladder_grid_is_crisp(self, font_manager):
+        """LADDER_GRID's BDF fonts are real bitmaps — always 0% antialiased."""
+        for step in LADDER_GRID:
+            font = font_manager.get_font(step.family, step.size_px)
+            assert measure_font_crispness(font, "Ay0") == 0.0
+
+    def test_ladder_arcade_is_crisp(self, font_manager):
+        """PressStart2P only rasterizes without antialiasing at exact
+        multiples of its 8px design grid — every LADDER_ARCADE rung must
+        land on one."""
+        for step in LADDER_ARCADE:
+            assert step.size_px % 8 == 0, f"{step} is not a multiple of 8"
+            font = font_manager.get_font(step.family, step.size_px)
+            assert measure_font_crispness(font, "17-21") == 0.0
+
+    def test_crispness_catches_a_bad_size(self, font_manager):
+        """Sanity check the measurement itself: a known-bad size for a
+        pixel-grid font must NOT read as crisp."""
+        font = font_manager.get_font("press_start", 10)  # not a multiple of 8
+        assert measure_font_crispness(font, "17-21") > 0.1
+
+    def test_fit_text_grows_on_taller_panel(self, font_manager):
+        small = LayoutContext(64, 32, font_manager)
+        large = LayoutContext(128, 64, font_manager)
+        text = "12:34"
+        fit_small = small.fit_text(text, small.bounds, ladder=LADDER_ARCADE)
+        fit_large = large.fit_text(text, large.bounds, ladder=LADDER_ARCADE)
+        assert fit_small.fits and fit_large.fits
+        assert fit_large.size_px > fit_small.size_px
+
+    def test_fit_text_fits_the_box(self, ctx):
+        box = ctx.bounds.inset(1)
+        fit = ctx.fit_text("HELLO WORLD", box)
+        assert fit.fits
+        assert fit.width <= box.w and fit.height <= box.h
+
+    def test_fit_text_ellipsizes_overlong_text(self, font_manager):
+        tiny = LayoutContext(32, 16, font_manager)
+        fit = tiny.fit_text("SUPERCALIFRAGILISTIC", tiny.bounds)
+        assert fit.text != "SUPERCALIFRAGILISTIC"
+        assert fit.text.endswith("…")
+        assert fit.width <= tiny.bounds.w
+
+    def test_fit_text_cached(self, ctx):
+        first = ctx.fit_text("CACHED", ctx.bounds)
+        second = ctx.fit_text("CACHED", ctx.bounds)
+        assert first is second
+        ctx.clear_cache()
+        assert ctx.fit_text("CACHED", ctx.bounds) is not first
+
+    def test_fit_text_proportional_tracks_design_scale(self, font_manager):
+        # design size 128x32, base_size_px=10 (a typical classic score size):
+        # at 2x scale the target is 20px -> nearest LADDER_ARCADE rung <= 20
+        # is 16px, not the largest that merely fits the box (32).
+        ctx = LayoutContext(256, 64, font_manager)  # scale = min(2,2) = 2
+        fit = ctx.fit_text_proportional("17-21", ctx.bounds, base_size_px=10,
+                                        ladder=LADDER_ARCADE)
+        assert fit.size_px == 16
+
+    def test_fit_text_proportional_does_not_exceed_max_fit(self, ctx):
+        # at scale=1 (128x32, the design size itself) the target equals
+        # base_size_px, so proportional should never pick something LARGER
+        # than plain fit_text would for the same box.
+        prop = ctx.fit_text_proportional("17-21", ctx.bounds, base_size_px=10,
+                                         ladder=LADDER_ARCADE)
+        maxed = ctx.fit_text("17-21", ctx.bounds, ladder=LADDER_ARCADE)
+        assert prop.size_px <= maxed.size_px
+
+    def test_fit_text_proportional_floors_at_smallest_rung(self, font_manager):
+        # scale so small the target is below every rung -> use the smallest
+        # rung as a floor rather than refusing to render anything.
+        ctx = LayoutContext(32, 8, font_manager)  # scale = min(32/128, 8/32) = 0.25
+        fit = ctx.fit_text_proportional("HI", ctx.bounds, base_size_px=10,
+                                        ladder=LADDER_ARCADE)
+        assert fit.size_px == min(s.size_px for s in LADDER_ARCADE)
+
+    def test_fit_text_proportional_falls_through_when_target_rung_overflows(self, font_manager):
+        # a long string at the target rung might not fit a narrow box even
+        # though the target size is "correct" -- must fall through to a
+        # smaller rung exactly like fit_text does, not just refuse to fit.
+        ctx = LayoutContext(256, 64, font_manager)
+        narrow_box = Region(0, 0, 40, 64)
+        fit = ctx.fit_text_proportional("A REALLY LONG STRING HERE", narrow_box,
+                                        base_size_px=10, ladder=LADDER_ARCADE)
+        assert fit.fits or fit.text.endswith("…")
+
+    def test_fit_text_proportional_cached(self, ctx):
+        first = ctx.fit_text_proportional("X", ctx.bounds, base_size_px=10)
+        second = ctx.fit_text_proportional("X", ctx.bounds, base_size_px=10)
+        assert first is second
+
+    def test_fit_text_proportional_scale_override(self, font_manager):
+        # 128x64 vs design 128x32: self.scale (min of both axes) is 1.0
+        # since width didn't grow, but a caller whose composition scales by
+        # HEIGHT alone (e.g. logo_slot = min(h, w//2)) should be able to
+        # override the reference scale so text grows with it too.
+        ctx = LayoutContext(128, 64, font_manager)
+        assert ctx.scale == 1.0
+        default_fit = ctx.fit_text_proportional("17-21", ctx.bounds, base_size_px=10,
+                                                 ladder=LADDER_ARCADE)
+        height_scale = 64 / 32  # matches design height
+        scaled_fit = ctx.fit_text_proportional("17-21", ctx.bounds, base_size_px=10,
+                                                ladder=LADDER_ARCADE, scale=height_scale)
+        assert scaled_fit.size_px > default_fit.size_px
+
+    def test_fit_lines_stacks_within_height(self, ctx):
+        box = ctx.bounds
+        lines = ["LINE ONE", "LINE TWO", "LINE THREE"]
+        fit = ctx.fit_lines(lines, box, spacing=1)
+        assert fit.fits
+        assert 3 * fit.line_height + 2 <= box.h
+
+    def test_font_for_rows(self, ctx):
+        fit = ctx.font_for_rows(4, 32)
+        assert fit.fits
+        assert 4 * fit.line_height <= 32
+
+    def test_ellipsize_returns_original_when_it_fits(self, ctx):
+        font = ctx.font_manager.get_font("4x6", 6)
+        assert ctx.ellipsize("HI", font, 1000) == "HI"
+
+
+class TestDrawFittedText:
+    def test_draws_within_region(self, ctx):
+        calls = []
+
+        class _DM:
+            def draw_text(self, text, x=None, y=None, color=None, font=None):
+                calls.append((text, x, y))
+
+        box = Region(10, 4, 100, 24)
+        fit = ctx.fit_text("SCORE", box)
+        draw_fitted_text(_DM(), fit, box)
+        text, x, y = calls[0]
+        assert text == "SCORE"
+        assert box.x <= x <= box.right - fit.width
+        # the ink (y + y_offset .. + height) must land inside the box
+        assert box.y <= y + fit.y_offset
+        assert y + fit.y_offset + fit.height <= box.bottom
+
+
+class TestBasePluginIntegration:
+    def test_layout_property_and_draw_fit(self):
+        from src.plugin_system.base_plugin import BasePlugin
+        from src.plugin_system.testing.mocks import (
+            MockCacheManager, MockDisplayManager, MockPluginManager,
+        )
+
+        class _Plugin(BasePlugin):
+            def update(self):
+                pass
+
+            def display(self, force_clear=False):
+                pass
+
+        plugin = _Plugin("test-plugin", {}, MockDisplayManager(96, 48),
+                         MockCacheManager(), MockPluginManager())
+        assert (plugin.layout.width, plugin.layout.height) == (96, 48)
+        assert plugin.layout is plugin.layout  # cached
+        fit = plugin.draw_fit("HELLO", plugin.layout.bounds.inset(1))
+        assert fit.fits
+        assert plugin.display_manager.draw_calls  # actually drew
+
+    def test_layout_rebuilds_on_size_change(self):
+        from src.plugin_system.base_plugin import BasePlugin
+        from src.plugin_system.testing.mocks import (
+            MockCacheManager, MockDisplayManager, MockPluginManager,
+        )
+
+        class _Plugin(BasePlugin):
+            def update(self):
+                pass
+
+            def display(self, force_clear=False):
+                pass
+
+        dm = MockDisplayManager(128, 32)
+        plugin = _Plugin("test-plugin", {}, dm,
+                         MockCacheManager(), MockPluginManager())
+        assert plugin.layout.tier == "sm"
+        dm.width, dm.height = 128, 64
+        assert plugin.layout.tier == "lg"
+
+    def test_design_size_from_manifest(self):
+        from src.plugin_system.base_plugin import BasePlugin
+        from src.plugin_system.testing.mocks import (
+            MockCacheManager, MockDisplayManager, MockPluginManager,
+        )
+
+        class _Plugin(BasePlugin):
+            def update(self):
+                pass
+
+            def display(self, force_clear=False):
+                pass
+
+        pm = MockPluginManager()
+        pm.plugin_manifests["test-plugin"] = {
+            "display": {"design_size": {"width": 64, "height": 32}}
+        }
+        plugin = _Plugin("test-plugin", {}, MockDisplayManager(128, 64),
+                         MockCacheManager(), pm)
+        assert plugin.layout.design_size == (64, 32)
+        assert plugin.layout.scale == 2.0
+
+
+class TestFitCacheBound:
+    def test_fit_cache_is_lru_bounded(self, ctx):
+        """A plugin fitting changing text (live game clock, ticker) on a
+        24/7 service must not grow the fit cache without bound."""
+        for i in range(ctx._FIT_CACHE_MAX + 100):
+            ctx.fit_text(f"tick {i}", Region(0, 0, 100, 20))
+        assert len(ctx._fit_cache) <= ctx._FIT_CACHE_MAX
+
+    def test_lru_keeps_recent_entries_hot(self, ctx):
+        hot = ctx.fit_text("stay hot", Region(0, 0, 100, 20))
+        for i in range(ctx._FIT_CACHE_MAX - 1):
+            ctx.fit_text(f"cold {i}", Region(0, 0, 100, 20))
+            ctx.fit_text("stay hot", Region(0, 0, 100, 20))  # keep touching it
+        assert ctx.fit_text("stay hot", Region(0, 0, 100, 20)) is hot

test/test_async_plugin_updates.py

@@ -0,0 +1,270 @@
+"""Tests for asynchronous plugin updates (plugin_manager background worker).
+
+The invariants that keep this change safe:
+1. run_scheduled_updates returns immediately — a slow update() can never
+   again freeze the render loop (the original defect: 30s scroll freezes).
+2. A plugin's update() and display() are NEVER concurrent — the per-plugin
+   lock makes the old implicit no-overlap guarantee explicit, and it stays
+   held through PluginExecutor's own timeout: a lingering, still-running
+   update() keeps the lock even after PluginExecutor gives up waiting on it.
+3. Failure/timeout bookkeeping is unchanged (same executor, same
+   _record_update_failure path, same last-update stamping).
+4. The kill switch (plugin_system.synchronous_updates) restores the
+   inline path exactly.
+"""
+
+import os
+import sys
+import threading
+import time
+
+import pytest
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), ".."))
+
+from src.plugin_system.plugin_manager import PluginManager  # noqa: E402
+from src.plugin_system.plugin_state import PluginState  # noqa: E402
+
+
+class SlowPlugin:
+    """Fake plugin whose update() sleeps and records overlap violations."""
+
+    def __init__(self, update_seconds=0.5):
+        self.enabled = True
+        self.update_seconds = update_seconds
+        self.update_calls = 0
+        self.display_calls = 0
+        self.in_update = False
+        self.overlap_detected = False
+
+    def update(self):
+        self.in_update = True
+        self.update_calls += 1
+        time.sleep(self.update_seconds)
+        self.in_update = False
+        return True
+
+    def display(self, force_clear=False):
+        if self.in_update:
+            self.overlap_detected = True
+        self.display_calls += 1
+        return True
+
+
+@pytest.fixture
+def pm(tmp_path):
+    manager = PluginManager(plugins_dir=str(tmp_path), config_manager=None,
+                            display_manager=None, cache_manager=None)
+    yield manager
+    manager.stop_update_worker()
+
+
+def _install(pm, plugin, plugin_id="slow-plugin"):
+    pm.plugins[plugin_id] = plugin
+    pm._update_interval_cache[plugin_id] = 0.01  # always due
+    # load_plugin normally registers state; can_execute() gates on it
+    pm.state_manager.set_state(plugin_id, PluginState.ENABLED)
+    return plugin_id
+
+
+class TestSchedulerNonBlocking:
+    def test_run_scheduled_updates_returns_immediately(self, pm):
+        plugin_id = _install(pm, SlowPlugin(update_seconds=2.0))
+        start = time.monotonic()
+        pm.run_scheduled_updates()
+        elapsed = time.monotonic() - start
+        assert elapsed < 0.1, f"scheduler blocked for {elapsed:.2f}s"
+        # the update actually runs in the background
+        deadline = time.monotonic() + 5
+        while pm.plugins[plugin_id].update_calls == 0 and time.monotonic() < deadline:
+            time.sleep(0.05)
+        assert pm.plugins[plugin_id].update_calls == 1
+
+    def test_no_double_enqueue_while_pending(self, pm):
+        plugin_id = _install(pm, SlowPlugin(update_seconds=0.8))
+        for _ in range(20):
+            pm.run_scheduled_updates()
+            time.sleep(0.01)
+        time.sleep(1.5)  # let the single queued update finish
+        assert pm.plugins[plugin_id].update_calls == 1
+
+
+class TestUpdateDisplayExclusion:
+    def test_display_lock_held_during_update(self, pm):
+        plugin_id = _install(pm, SlowPlugin(update_seconds=0.6))
+        pm.run_scheduled_updates()
+        # give the worker a moment to take the lock and enter update()
+        deadline = time.monotonic() + 2
+        while not pm.plugins[plugin_id].in_update and time.monotonic() < deadline:
+            time.sleep(0.01)
+        lock = pm.get_plugin_lock(plugin_id)
+        assert lock.acquire(blocking=False) is False, \
+            "lock must be held while update() runs"
+        # and released afterwards
+        deadline = time.monotonic() + 3
+        while pm.plugins[plugin_id].in_update and time.monotonic() < deadline:
+            time.sleep(0.05)
+        time.sleep(0.1)
+        assert lock.acquire(blocking=False) is True
+        lock.release()
+
+    def test_no_overlap_under_hammering_display_loop(self, pm):
+        """Simulate the render loop's try-lock display pattern at high rate
+        while updates fire — the plugin itself asserts no overlap."""
+        plugin = SlowPlugin(update_seconds=0.15)
+        plugin_id = _install(pm, plugin)
+        stop = threading.Event()
+
+        def render_loop():
+            while not stop.is_set():
+                lock = pm.get_plugin_lock(plugin_id)
+                if lock.acquire(blocking=False):
+                    try:
+                        plugin.display()
+                    finally:
+                        lock.release()
+                time.sleep(0.002)
+
+        renderer = threading.Thread(target=render_loop, daemon=True)
+        renderer.start()
+        try:
+            for _ in range(6):
+                pm.plugin_last_update.pop(plugin_id, None)  # force due
+                pm.run_scheduled_updates()
+                time.sleep(0.3)
+        finally:
+            stop.set()
+            renderer.join(timeout=2)
+        assert plugin.update_calls >= 3
+        assert plugin.display_calls > 10
+        assert plugin.overlap_detected is False
+
+    def test_lock_held_through_timeout_until_real_update_finishes(self, pm):
+        """PluginExecutor's join(timeout) can return before the real
+        update() call does -- the lingering daemon thread keeps running it.
+        The plugin's lock must stay held for that whole real duration, not
+        just PluginExecutor's bounded wait, or display() could run
+        concurrently with a still-executing update()."""
+        plugin = SlowPlugin(update_seconds=0.3)
+        plugin_id = _install(pm, plugin)
+        pm.plugin_executor.default_timeout = 0.05  # times out well before
+                                                    # update_seconds elapses
+
+        pm.run_scheduled_updates()
+
+        deadline = time.monotonic() + 2
+        while not plugin.in_update and time.monotonic() < deadline:
+            time.sleep(0.01)
+        assert plugin.in_update is True
+
+        # PluginExecutor's own timeout has now elapsed, but the real
+        # update() (0.3s) is still running in its lingering daemon thread.
+        time.sleep(0.15)
+        assert plugin.in_update is True, "test setup: update should still be running"
+        lock = pm.get_plugin_lock(plugin_id)
+        assert lock.acquire(blocking=False) is False, \
+            "lock must stay held through PluginExecutor's timeout while the real update() runs"
+
+        # Once the real update() genuinely finishes, the lock is released.
+        deadline = time.monotonic() + 2
+        while plugin.in_update and time.monotonic() < deadline:
+            time.sleep(0.02)
+        time.sleep(0.1)
+        assert lock.acquire(blocking=False) is True
+        lock.release()
+
+    def test_state_returns_to_enabled_after_update(self, pm):
+        """RUNNING is set at enqueue (blocks re-entry via can_execute) and
+        must return to an executable state once the update finishes."""
+        plugin_id = _install(pm, SlowPlugin(update_seconds=0.1))
+        pm.run_scheduled_updates()
+        # while queued/running, re-entry is blocked
+        assert pm.state_manager.can_execute(plugin_id) is False
+        deadline = time.monotonic() + 3
+        while time.monotonic() < deadline:
+            if (pm.plugins[plugin_id].update_calls
+                    and pm.state_manager.can_execute(plugin_id)):
+                break
+            time.sleep(0.05)
+        assert pm.plugins[plugin_id].update_calls == 1
+        assert pm.state_manager.can_execute(plugin_id) is True
+
+
+class TestFailurePaths:
+    def test_update_failure_routes_through_failure_bookkeeping(self, pm):
+        class FailingPlugin(SlowPlugin):
+            def update(self):
+                self.update_calls += 1
+                raise RuntimeError("boom")
+
+        plugin_id = _install(pm, FailingPlugin())
+        pm.run_scheduled_updates()
+        deadline = time.monotonic() + 3
+        while pm.plugins[plugin_id].update_calls == 0 and time.monotonic() < deadline:
+            time.sleep(0.05)
+        time.sleep(0.2)
+        # failure stamped so the interval gate holds (no hot retry loop)
+        assert pm.plugin_last_update.get(plugin_id, 0) > 0
+        # lock released after failure
+        assert pm.get_plugin_lock(plugin_id).acquire(blocking=False) is True
+        pm.get_plugin_lock(plugin_id).release()
+
+    def test_unloaded_while_queued_is_harmless(self, pm):
+        """Exercise the public unload_plugin() lifecycle rather than
+        deleting pm.plugins directly: queue the target's update behind a
+        deterministic blocker (occupying the single worker), unload the
+        target while its item still sits queued, then release the blocker
+        and confirm the target's update never ran and its state stayed
+        unloaded rather than being resurrected to ENABLED."""
+        blocker_event = threading.Event()
+
+        class BlockerPlugin(SlowPlugin):
+            def update(self):
+                self.update_calls += 1
+                blocker_event.wait(timeout=5)
+                return True
+
+        blocker_id = _install(pm, BlockerPlugin(), plugin_id="blocker-plugin")
+        target = SlowPlugin(update_seconds=0.05)
+        target_id = _install(pm, target, plugin_id="slow-plugin")
+
+        # Dispatch the blocker first so it occupies the single worker
+        # thread, then enqueue the target behind it -- deterministically
+        # queued, not yet started.
+        pm._enqueue_update(blocker_id, time.time())
+        deadline = time.monotonic() + 2
+        while pm.plugins[blocker_id].update_calls == 0 and time.monotonic() < deadline:
+            time.sleep(0.01)
+        assert pm.plugins[blocker_id].update_calls == 1
+
+        pm._enqueue_update(target_id, time.time())
+        assert target_id in pm._pending_updates
+
+        assert pm.unload_plugin(target_id) is True
+        assert target_id not in pm.plugins
+
+        blocker_event.set()  # let the blocker finish; worker moves on to
+                              # the target's queued item
+
+        deadline = time.monotonic() + 3
+        while target_id in pm._pending_updates and time.monotonic() < deadline:
+            time.sleep(0.02)
+
+        assert target.update_calls == 0, "update() must not run for an unloaded plugin"
+        assert target_id not in pm._pending_updates
+        assert pm.state_manager.get_state(target_id) == PluginState.UNLOADED
+
+
+class TestKillSwitch:
+    def test_synchronous_mode_blocks_like_before(self, pm):
+        pm._synchronous_updates = True
+        plugin_id = _install(pm, SlowPlugin(update_seconds=0.4))
+        start = time.monotonic()
+        pm.run_scheduled_updates()
+        elapsed = time.monotonic() - start
+        assert elapsed >= 0.4, "synchronous mode must run inline"
+        assert pm.plugins[plugin_id].update_calls == 1
+
+
+if __name__ == "__main__":
+    sys.exit(pytest.main([__file__, "-v"]))

test/test_cache_manager.py

@@ -279,10 +279,23 @@ class TestDiskCache:
         """Test getting expired cache entry."""
         cache = DiskCache(cache_dir=str(tmp_path))
         cache.set("test_key", {"data": "value"})
-        
+
         # Get with max_age=0 to force expiration
         result = cache.get("test_key", max_age=0)
         assert result is None
+
+    def test_get_max_age_none_never_expires(self, tmp_path):
+        """max_age=None must return persisted records regardless of age.
+
+        Regression: the age comparison raised TypeError for max_age=None,
+        which was swallowed and treated as a miss — silently breaking
+        long-lived state (plugin health/metrics) read across processes.
+        """
+        cache = DiskCache(cache_dir=str(tmp_path))
+        cache.set("test_key", {"data": "value", "timestamp": 0})  # epoch → very old
+        result = cache.get("test_key", max_age=None)
+        assert result is not None
+        assert result["data"] == "value"
     
     def test_get_nonexistent(self, tmp_path):
         """Test getting non-existent key."""
@@ -387,3 +400,61 @@ class TestDiskCache:
         assert stats['fetch_count'] == 3
         assert stats['total_fetch_time'] == 1.8
         assert stats['average_fetch_time'] == pytest.approx(0.6, abs=0.01)
+
+
+class TestDiskCacheWriteEconomy:
+    """SD-card wear guards: identical payloads skip the disk, files are
+    compact, and TTL semantics survive the skip (see PR: fix/diskcache-sd-wear)."""
+
+    def test_identical_set_skips_rewrite(self, tmp_path):
+        import os
+        cache = DiskCache(cache_dir=str(tmp_path))
+        cache.set("k", {"data": "v"})
+        path = cache.get_cache_path("k")
+        first = os.stat(path)
+        os.utime(path, (first.st_atime - 100, first.st_mtime - 100))  # age it
+        aged_mtime = os.stat(path).st_mtime
+        ino_before = os.stat(path).st_ino
+        cache.set("k", {"data": "v"})  # identical payload
+        after = os.stat(path)
+        # mtime refreshed (TTL for mtime-based records preserved)...
+        assert after.st_mtime > aged_mtime
+        # ...but the file was NOT rewritten (same inode: no replace happened)
+        assert after.st_ino == ino_before
+
+    def test_changed_data_rewrites(self, tmp_path):
+        import os
+        cache = DiskCache(cache_dir=str(tmp_path))
+        cache.set("k", {"data": "v1"})
+        cache.set("k", {"data": "v2"})
+        assert cache.get("k") == {"data": "v2"}
+
+    def test_clear_resets_digest(self, tmp_path):
+        import os
+        cache = DiskCache(cache_dir=str(tmp_path))
+        cache.set("k", {"data": "v"})
+        cache.clear("k")
+        assert cache.get("k") is None
+        cache.set("k", {"data": "v"})  # same payload after clear must WRITE
+        assert cache.get("k") == {"data": "v"}
+
+    def test_skip_self_heals_when_file_deleted_externally(self, tmp_path):
+        import os
+        cache = DiskCache(cache_dir=str(tmp_path))
+        cache.set("k", {"data": "v"})
+        os.remove(cache.get_cache_path("k"))  # e.g. expiry cleanup
+        cache.set("k", {"data": "v"})  # digest matches but file is gone
+        assert cache.get("k") == {"data": "v"}
+
+    def test_files_are_compact_json(self, tmp_path):
+        cache = DiskCache(cache_dir=str(tmp_path))
+        cache.set("k", {"a": 1, "b": [1, 2, 3]})
+        raw = open(cache.get_cache_path("k")).read()
+        assert "\n" not in raw.strip()  # no indent
+        assert cache.get("k") == {"a": 1, "b": [1, 2, 3]}
+
+    def test_datetime_round_trip_still_works(self, tmp_path):
+        from datetime import datetime
+        cache = DiskCache(cache_dir=str(tmp_path))
+        cache.set("k", {"when": datetime(2026, 7, 12, 10, 30)})
+        assert cache.get("k") == {"when": "2026-07-12T10:30:00"}

test/test_config_load_cache.py

@@ -0,0 +1,129 @@
+"""Tests for load_config's mtime fast path (src/config_manager.py).
+
+load_config used to re-read + re-parse config.json, the template (with a
+recursive migration diff) and secrets on EVERY call — ~30 web request
+handlers call it, some 2-3x per request. The fast path skips all of it
+when the three files' (mtime_ns, size) signatures are unchanged.
+
+The invariant that matters most: cross-process freshness — a save from
+the web process must be picked up by the display process's next load.
+That's guaranteed because the signature is re-stat'd on every call.
+"""
+
+import json
+import os
+import sys
+
+import pytest
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), ".."))
+
+from src.config_manager import ConfigManager  # noqa: E402
+
+
+@pytest.fixture
+def mgr(tmp_path):
+    config = tmp_path / "config.json"
+    secrets = tmp_path / "secrets.json"
+    template = tmp_path / "template.json"
+    config.write_text(json.dumps({"display": {"brightness": 90}, "timezone": "UTC"}))
+    secrets.write_text(json.dumps({"weather": {"api_key": "sek"}}))
+    template.write_text(json.dumps({"display": {"brightness": 90}, "timezone": "UTC"}))
+    m = ConfigManager(config_path=str(config), secrets_path=str(secrets))
+    m.template_path = str(template)
+    return m, config, secrets, template
+
+
+def _count_opens(monkeypatch, mgr_paths):
+    """Count open() calls hitting the config files."""
+    counts = {"n": 0}
+    real_open = open
+
+    def counting_open(file, *args, **kwargs):
+        if str(file) in mgr_paths:
+            counts["n"] += 1
+        return real_open(file, *args, **kwargs)
+
+    import builtins
+    monkeypatch.setattr(builtins, "open", counting_open)
+    return counts
+
+
+class TestFastPath:
+    def test_unchanged_files_are_not_reread(self, mgr, monkeypatch):
+        m, config, secrets, template = mgr
+        first = m.load_config()
+        assert first["weather"]["api_key"] == "sek"  # secrets merged
+        counts = _count_opens(monkeypatch, {str(config), str(secrets), str(template)})
+        for _ in range(10):
+            again = m.load_config()
+        assert counts["n"] == 0, "fast path must not re-open any config file"
+        assert again is first  # same aliasing semantics as the full path
+
+    def test_config_change_triggers_reload(self, mgr):
+        m, config, secrets, template = mgr
+        m.load_config()
+        data = json.loads(config.read_text())
+        data["display"]["brightness"] = 55
+        config.write_text(json.dumps(data))
+        os.utime(config, (os.stat(config).st_atime, os.stat(config).st_mtime + 2))
+        assert m.load_config()["display"]["brightness"] == 55
+
+    def test_secrets_change_triggers_reload(self, mgr):
+        m, config, secrets, template = mgr
+        m.load_config()
+        secrets.write_text(json.dumps({"weather": {"api_key": "NEW"}}))
+        os.utime(secrets, (os.stat(secrets).st_atime, os.stat(secrets).st_mtime + 2))
+        assert m.load_config()["weather"]["api_key"] == "NEW"
+
+    def test_template_change_triggers_reload_and_migration(self, mgr):
+        m, config, secrets, template = mgr
+        m.load_config()
+        template.write_text(json.dumps({
+            "display": {"brightness": 90}, "timezone": "UTC",
+            "brand_new_key": {"added": True}}))
+        os.utime(template, (os.stat(template).st_atime, os.stat(template).st_mtime + 2))
+        reloaded = m.load_config()
+        assert reloaded.get("brand_new_key") == {"added": True}
+
+    def test_same_second_edit_detected_via_mtime_ns_or_size(self, mgr):
+        """Coarse-mtime same-second edits: size difference still busts it."""
+        m, config, secrets, template = mgr
+        m.load_config()
+        st = os.stat(config)
+        data = json.loads(config.read_text())
+        data["timezone"] = "America/New_York"  # different byte length
+        config.write_text(json.dumps(data))
+        os.utime(config, (st.st_atime, st.st_mtime))  # force same mtime
+        assert m.load_config()["timezone"] == "America/New_York"
+
+
+class TestSaveCoherence:
+    def test_save_config_then_load_returns_saved_data(self, mgr, monkeypatch):
+        m, config, secrets, template = mgr
+        m.load_config()
+        new = {"display": {"brightness": 42}, "timezone": "UTC",
+               "weather": {"api_key": "sek"}}
+        m.save_config(new)
+        counts = _count_opens(monkeypatch, {str(config), str(secrets), str(template)})
+        loaded = m.load_config()
+        assert loaded["display"]["brightness"] == 42
+        assert loaded["weather"]["api_key"] == "sek"  # secrets survive in memory
+        assert counts["n"] == 0  # signature refreshed by save; no re-read
+
+    def test_cross_process_save_is_picked_up(self, mgr):
+        """Another process writing config.json (different mtime) must bust
+        this process's fast path — the core cross-process guarantee."""
+        m, config, secrets, template = mgr
+        m.load_config()
+        other = ConfigManager(config_path=str(config), secrets_path=str(secrets))
+        other.template_path = str(template)
+        other.load_config()
+        other.save_config({"display": {"brightness": 11}, "timezone": "UTC",
+                           "weather": {"api_key": "sek"}})
+        os.utime(config, (os.stat(config).st_atime, os.stat(config).st_mtime + 2))
+        assert m.load_config()["display"]["brightness"] == 11
+
+
+if __name__ == "__main__":
+    sys.exit(pytest.main([__file__, "-v"]))

test/test_display_controller.py

@@ -391,3 +391,16 @@ class TestDisplayControllerSchedule:
 
             controller._check_schedule()
             assert controller.is_display_active is False
+
+
+class TestPluginHealthWiring:
+    """Phase 1: DisplayController activates the dormant plugin health/metrics
+    subsystem by wiring real tracker/monitor instances onto the plugin manager."""
+
+    def test_health_tracker_and_resource_monitor_wired(self, test_display_controller):
+        from src.plugin_system.plugin_health import PluginHealthTracker
+        from src.plugin_system.resource_monitor import PluginResourceMonitor
+
+        pm = test_display_controller.plugin_manager
+        assert isinstance(pm.health_tracker, PluginHealthTracker)
+        assert isinstance(pm.resource_monitor, PluginResourceMonitor)

test/test_display_controller_plugin_toggle.py

@@ -0,0 +1,255 @@
+"""Tests for live plugin enable/disable hot-reload in DisplayController.
+
+Enabling or disabling a plugin in config used to require a full display
+restart because the plugin list and available_modes were built once at init.
+These tests cover the reconcile path that loads/unloads plugins and rebuilds
+the dispatch maps on the main thread when the enabled set changes.
+"""
+
+from unittest.mock import MagicMock
+
+
+def _make_plugin(modes):
+    plugin = MagicMock()
+    plugin.modes = list(modes)
+    return plugin
+
+
+def _wire_plugin_manager(controller, plugins, discovered=None):
+    """Point the controller's mock plugin_manager at a set of fake plugins.
+
+    `plugins` maps plugin_id -> mock instance (with a .modes list).
+    """
+    pm = controller.plugin_manager
+    pm.discover_plugins.return_value = list(discovered if discovered is not None else plugins.keys())
+    pm.load_plugin.return_value = True
+    pm.unload_plugin.return_value = True
+    pm.plugin_manifests = {}
+    pm.get_plugin.side_effect = lambda pid: plugins.get(pid)
+    return pm
+
+
+def _set_config(controller, cfg):
+    controller.config_service.get_config = lambda: cfg
+
+
+class TestPluginEnableDisableHotReload:
+    def test_enable_plugin_live(self, test_display_controller):
+        controller = test_display_controller
+        assert controller.available_modes == []
+
+        plugin = _make_plugin(["foo"])
+        _wire_plugin_manager(controller, {"foo": plugin})
+        _set_config(controller, {"foo": {"enabled": True}})
+
+        controller._reconcile_enabled_plugins()
+
+        assert "foo" in controller.plugin_display_modes
+        assert "foo" in controller.available_modes
+        assert controller.plugin_modes["foo"] is plugin
+        assert controller.mode_to_plugin_id["foo"] == "foo"
+        controller.plugin_manager.load_plugin.assert_any_call("foo")
+
+    def test_disable_plugin_live(self, test_display_controller):
+        controller = test_display_controller
+        plugin = _make_plugin(["live", "recent"])
+        _wire_plugin_manager(controller, {"sports": plugin}, discovered=["sports"])
+
+        # Enable, then disable.
+        _set_config(controller, {"sports": {"enabled": True}})
+        controller._reconcile_enabled_plugins()
+        assert "sports" in controller.plugin_display_modes
+        assert "live" in controller.available_modes and "recent" in controller.available_modes
+        assert "sports" in controller._plugin_config_callbacks
+
+        _set_config(controller, {"sports": {"enabled": False}})
+        controller._reconcile_enabled_plugins()
+
+        assert "sports" not in controller.plugin_display_modes
+        assert "live" not in controller.available_modes
+        assert "recent" not in controller.available_modes
+        assert "live" not in controller.plugin_modes
+        assert "recent" not in controller.mode_to_plugin_id
+        controller.plugin_manager.unload_plugin.assert_any_call("sports")
+        assert "sports" not in controller._plugin_config_callbacks
+
+    def test_disable_clamps_current_mode_index(self, test_display_controller):
+        controller = test_display_controller
+        p1 = _make_plugin(["a"])
+        p2 = _make_plugin(["b"])
+        _wire_plugin_manager(controller, {"p1": p1, "p2": p2}, discovered=["p1", "p2"])
+
+        _set_config(controller, {"p1": {"enabled": True}, "p2": {"enabled": True}})
+        controller._reconcile_enabled_plugins()
+        # Add order across multiple plugins is set-driven (as at init), so
+        # compare membership, not order.
+        assert set(controller.available_modes) == {"a", "b"}
+
+        # Pretend we're currently showing p2's mode.
+        controller.current_mode_index = controller.available_modes.index("b")
+        controller.current_display_mode = "b"
+
+        _set_config(controller, {"p1": {"enabled": True}, "p2": {"enabled": False}})
+        controller._reconcile_enabled_plugins()
+
+        assert controller.available_modes == ["a"]
+        # Index must be back in range and the display mode no longer the removed one.
+        assert 0 <= controller.current_mode_index < len(controller.available_modes)
+        assert controller.current_display_mode == "a"
+
+    def test_enable_keeps_current_mode(self, test_display_controller):
+        controller = test_display_controller
+        p1 = _make_plugin(["a"])
+        p2 = _make_plugin(["b"])
+        _wire_plugin_manager(controller, {"p1": p1, "p2": p2}, discovered=["p1", "p2"])
+
+        _set_config(controller, {"p1": {"enabled": True}})
+        controller._reconcile_enabled_plugins()
+        controller.current_mode_index = 0
+        controller.current_display_mode = "a"
+
+        # Enabling p2 should not disturb the currently-showing mode.
+        _set_config(controller, {"p1": {"enabled": True}, "p2": {"enabled": True}})
+        controller._reconcile_enabled_plugins()
+
+        assert "b" in controller.available_modes
+        assert controller.current_display_mode == "a"
+        assert controller.available_modes[controller.current_mode_index] == "a"
+
+    def test_noop_when_enabled_set_unchanged(self, test_display_controller):
+        controller = test_display_controller
+        plugin = _make_plugin(["foo"])
+        _wire_plugin_manager(controller, {"foo": plugin}, discovered=["foo"])
+        _set_config(controller, {"foo": {"enabled": True}})
+        controller._reconcile_enabled_plugins()
+
+        load_calls = controller.plugin_manager.load_plugin.call_count
+        unload_calls = controller.plugin_manager.unload_plugin.call_count
+
+        # Reconcile again with no change — must not load/unload anything.
+        controller._reconcile_enabled_plugins()
+        assert controller.plugin_manager.load_plugin.call_count == load_calls
+        assert controller.plugin_manager.unload_plugin.call_count == unload_calls
+
+    def test_reconcile_ignores_non_dict_config_value(self, test_display_controller, caplog):
+        """A malformed config value (e.g. a stray string where a plugin's
+        section should be a dict) must be treated as disabled, not crash
+        the reconcile with AttributeError, and should be logged so it's
+        visible to whoever has to debug the malformed config."""
+        controller = test_display_controller
+        plugin = _make_plugin(["foo"])
+        _wire_plugin_manager(controller, {"foo": plugin}, discovered=["foo"])
+        _set_config(controller, {"foo": "not-a-dict"})
+
+        with caplog.at_level("WARNING"):
+            controller._reconcile_enabled_plugins()  # must not raise
+
+        assert "foo" not in controller.plugin_display_modes
+        assert "foo" not in controller.available_modes
+        assert any("foo" in r.message and "not a dict" in r.message for r in caplog.records)
+
+    def test_disable_keeps_callback_when_unsubscribe_fails(self, test_display_controller):
+        """If config_service.unsubscribe() raises, _unregister_plugin must
+        keep the callback in _plugin_config_callbacks rather than losing the
+        only reference to it (it still tears down the plugin itself)."""
+        controller = test_display_controller
+        plugin = _make_plugin(["live"])
+        _wire_plugin_manager(controller, {"sports": plugin}, discovered=["sports"])
+
+        _set_config(controller, {"sports": {"enabled": True}})
+        controller._reconcile_enabled_plugins()
+        assert "sports" in controller._plugin_config_callbacks
+
+        controller.config_service.unsubscribe = MagicMock(side_effect=RuntimeError("boom"))
+
+        _set_config(controller, {"sports": {"enabled": False}})
+        controller._reconcile_enabled_plugins()
+
+        assert "sports" not in controller.plugin_display_modes
+        assert "sports" in controller._plugin_config_callbacks
+
+
+class TestReconcileReturnValue:
+    """_reconcile_enabled_plugins() returns True/False so the caller (run()'s
+    loop) only clears _pending_plugin_reconcile on success, keeping a
+    retryable failure's request alive instead of silently dropping it."""
+
+    def test_returns_true_on_success(self, test_display_controller):
+        controller = test_display_controller
+        plugin = _make_plugin(["foo"])
+        _wire_plugin_manager(controller, {"foo": plugin}, discovered=["foo"])
+        _set_config(controller, {"foo": {"enabled": True}})
+        assert controller._reconcile_enabled_plugins() is True
+
+    def test_returns_true_for_noop(self, test_display_controller):
+        controller = test_display_controller
+        _wire_plugin_manager(controller, {}, discovered=[])
+        _set_config(controller, {})
+        assert controller._reconcile_enabled_plugins() is True
+
+    def test_returns_false_on_discovery_failure(self, test_display_controller):
+        controller = test_display_controller
+        controller.plugin_manager.discover_plugins.side_effect = RuntimeError("boom")
+        _set_config(controller, {})
+        assert controller._reconcile_enabled_plugins() is False
+
+    def test_returns_true_when_no_plugin_manager(self, test_display_controller):
+        controller = test_display_controller
+        controller.plugin_manager = None
+        assert controller._reconcile_enabled_plugins() is True
+
+
+class TestRunWithNoModesEnabled:
+    """Before hot-reload, an empty available_modes at startup was permanent
+    -- the display never came back without a restart. Now that a plugin can
+    be enabled live from the web UI, run() must idle rather than exit."""
+
+    def test_idles_instead_of_exiting(self, test_display_controller):
+        controller = test_display_controller
+        assert controller.available_modes == []
+
+        sleep_calls = []
+
+        def fake_sleep(duration, tick_interval=1.0):
+            sleep_calls.append(duration)
+            if len(sleep_calls) >= 3:
+                # Stand in for the process being torn down; run() catches
+                # this via its broad except + finally, same as any other
+                # unexpected error during the loop.
+                raise RuntimeError("stop-test-loop")
+
+        controller._sleep_with_plugin_updates = fake_sleep
+
+        controller.run()
+
+        # Old behavior returned before ever reaching the loop body, so
+        # _sleep_with_plugin_updates would never have been called. The idle
+        # tick is short (not a long sleep) so a plugin enabled via the web
+        # UI while idle is picked up about as promptly as it would be once
+        # modes exist and the loop is iterating per-frame.
+        assert sleep_calls == [1, 1, 1]
+
+
+class TestEnabledSetChanged:
+    def test_detects_toggle(self, test_display_controller):
+        c = test_display_controller
+        assert c._enabled_set_changed({"a": {"enabled": True}}, {"a": {"enabled": False}}) is True
+
+    def test_no_change(self, test_display_controller):
+        c = test_display_controller
+        cfg = {"a": {"enabled": True}, "b": {"enabled": False}}
+        assert c._enabled_set_changed(cfg, dict(cfg)) is False
+
+    def test_new_enabled_section(self, test_display_controller):
+        c = test_display_controller
+        assert c._enabled_set_changed(
+            {"a": {"enabled": True}},
+            {"a": {"enabled": True}, "b": {"enabled": True}},
+        ) is True
+
+    def test_ignores_non_enabled_value_edits(self, test_display_controller):
+        c = test_display_controller
+        assert c._enabled_set_changed(
+            {"a": {"enabled": True, "duration": 30}},
+            {"a": {"enabled": True, "duration": 45}},
+        ) is False

test/test_display_controller_vegas_tick.py

@@ -0,0 +1,88 @@
+"""
+Regression tests for DisplayController._tick_plugin_updates_for_vegas().
+
+PR #299 added logic to detect which plugins actually got fresh data on a
+scheduled-update tick and notify Vegas mode via
+vegas_coordinator.mark_plugin_updated(), so a live score change reaches the
+scroll within seconds instead of waiting for a full cycle. PR #330's
+multi-display sync refactor deleted this method (folding the callback back
+to the plain _tick_plugin_updates(), which reports nothing), silently
+orphaning VegasModeCoordinator.mark_plugin_updated() -- it has had zero
+callers since.
+"""
+
+from typing import Dict, List, Optional
+from unittest.mock import MagicMock
+
+from src.display_controller import DisplayController
+
+
+def _make_controller(updated: Optional[List[str]] = None, vegas_coordinator: Optional[MagicMock] = None) -> DisplayController:
+    dc = object.__new__(DisplayController)
+    dc.plugin_manager = MagicMock()
+    dc.plugin_manager.run_scheduled_updates_with_changes.return_value = list(updated or [])
+    dc.vegas_coordinator = vegas_coordinator
+    return dc
+
+
+class TestTickPluginUpdatesForVegas:
+    def test_marks_only_plugins_whose_timestamp_advanced(self):
+        vc = MagicMock()
+        dc = _make_controller(updated=["stock-news"], vegas_coordinator=vc)
+
+        dc._tick_plugin_updates_for_vegas()
+
+        vc.mark_plugin_updated.assert_called_once_with("stock-news")
+
+    def test_no_advance_marks_nothing(self):
+        vc = MagicMock()
+        dc = _make_controller(updated=[], vegas_coordinator=vc)
+
+        dc._tick_plugin_updates_for_vegas()
+
+        vc.mark_plugin_updated.assert_not_called()
+
+    def test_no_vegas_coordinator_does_not_raise(self):
+        dc = _make_controller(updated=["stock-news"], vegas_coordinator=None)
+
+        dc._tick_plugin_updates_for_vegas()  # must not raise
+
+    def test_mark_plugin_updated_exception_does_not_propagate(self):
+        """One plugin's mark_plugin_updated failing must not stop the tick
+        or crash the update loop it runs in."""
+        vc = MagicMock()
+        vc.mark_plugin_updated.side_effect = [RuntimeError("boom"), None]
+        dc = _make_controller(updated=["a", "b"], vegas_coordinator=vc)
+
+        dc._tick_plugin_updates_for_vegas()  # must not raise
+
+        assert vc.mark_plugin_updated.call_count == 2
+
+
+class TestVegasCoordinatorCallbackWiring:
+    def test_initialize_wires_vegas_aware_tick_as_update_callback(self):
+        """The Vegas coordinator must be given the Vegas-aware
+        _tick_plugin_updates_for_vegas as its update callback, not the plain
+        _tick_plugin_updates() -- that's the exact wiring PR #330 dropped."""
+        dc = object.__new__(DisplayController)
+        dc.config = {"display": {"vegas_scroll": {"enabled": True}}, "sync": {}}
+        dc.display_manager = MagicMock()
+        dc.plugin_manager = MagicMock()
+        dc.sync_manager = MagicMock()
+        dc._check_live_priority = MagicMock()
+        dc._check_vegas_interrupt = MagicMock(return_value=False)
+
+        fake_coordinator = MagicMock()
+
+        import src.display_controller as dc_module
+        original_imported = dc_module._vegas_mode_imported
+        original_class = dc_module.VegasModeCoordinator
+        try:
+            dc_module._vegas_mode_imported = True
+            dc_module.VegasModeCoordinator = MagicMock(return_value=fake_coordinator)
+            dc._initialize_vegas_mode()
+        finally:
+            dc_module._vegas_mode_imported = original_imported
+            dc_module.VegasModeCoordinator = original_class
+
+        fake_coordinator.set_update_callback.assert_called_once_with(dc._tick_plugin_updates_for_vegas)

test/test_display_dirty_tracking.py

@@ -0,0 +1,162 @@
+"""Tests for update_display dirty tracking (src/display_manager.py).
+
+Runs against RGBMatrixEmulator (EMULATOR=true), exercising the REAL
+DisplayManager — not a mock — so the skip logic, its invalidation hooks,
+and the kill switch are verified off-Pi.
+
+The invariants:
+- identical frames are pushed exactly once (SwapOnVSync not re-called)
+- ANY pixel change pushes
+- clear() and set_brightness() invalidate (the two paths that alter panel
+  state outside the digest's view)
+- the kill switch (display.dirty_tracking: false) restores always-push
+"""
+
+import os
+import sys
+import time
+
+os.environ["EMULATOR"] = "true"
+
+import pytest
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), ".."))
+
+
+@pytest.fixture(scope="module")
+def dm():
+    """One real DisplayManager on the emulator (it's a process singleton)."""
+    from src.display_manager import DisplayManager
+    DisplayManager._instance = None
+    DisplayManager._initialized = False
+    manager = DisplayManager({
+        "display": {
+            "hardware": {"rows": 32, "cols": 64, "chain_length": 2,
+                         "parallel": 1, "brightness": 90},
+            "runtime": {"gpio_slowdown": 0},
+        },
+    }, suppress_test_pattern=True)
+    yield manager
+    DisplayManager._instance = None
+    DisplayManager._initialized = False
+
+
+class _SwapSpy:
+    """Counts SwapOnVSync calls through the real matrix object."""
+
+    def __init__(self, matrix):
+        self.matrix = matrix
+        self.count = 0
+        self._orig = matrix.SwapOnVSync
+
+    def __enter__(self):
+        def counting(canvas):
+            self.count += 1
+            return self._orig(canvas)
+        self.matrix.SwapOnVSync = counting
+        return self
+
+    def __exit__(self, *exc):
+        self.matrix.SwapOnVSync = self._orig
+
+
+class TestDirtyTracking:
+    def test_identical_frames_push_once(self, dm):
+        dm.draw.rectangle([0, 0, 10, 10], fill=(255, 0, 0))
+        with _SwapSpy(dm.matrix) as spy:
+            dm.update_display()
+            dm.update_display()
+            dm.update_display()
+        assert spy.count == 1
+
+    def test_pixel_change_pushes(self, dm):
+        dm.update_display()
+        with _SwapSpy(dm.matrix) as spy:
+            dm.draw.point((5, 5), fill=(0, 255, 0))
+            dm.update_display()
+            dm.update_display()  # unchanged again
+        assert spy.count == 1
+
+    def test_clear_invalidates(self, dm):
+        dm.draw.rectangle([0, 0, 20, 20], fill=(0, 0, 255))
+        dm.update_display()
+        dm.clear()  # writes to the matrix directly; digest must reset
+        with _SwapSpy(dm.matrix) as spy:
+            dm.update_display()  # black frame after clear must still push
+        assert spy.count == 1
+
+    def test_brightness_change_forces_push(self, dm):
+        dm.draw.rectangle([0, 0, 20, 20], fill=(200, 200, 200))
+        dm.update_display()
+        with _SwapSpy(dm.matrix) as spy:
+            dm.update_display()          # identical -> skipped
+            assert spy.count == 0
+            dm.set_brightness(40)        # dim schedule scenario
+            dm.update_display()          # same image, new brightness -> push
+        assert spy.count == 1
+        dm.set_brightness(90)
+
+    def test_snapshot_still_written_on_skip(self, dm, tmp_path):
+        """The web preview mirror must keep working through skipped panel
+        pushes: _write_snapshot_if_due() still runs on the dirty-tracking
+        skip path and applies its own write/touch policy rather than being
+        bypassed entirely (see src/common/snapshot_policy.py — an unchanged
+        frame is touched, not re-encoded, once TOUCH_INTERVAL elapses)."""
+        dm._snapshot_path = str(tmp_path / "snap.png")
+        dm._last_snapshot_ts = 0.0
+        dm._last_snapshot_touch_ts = 0.0
+        dm._last_snapshot_digest = None
+        dm.draw.rectangle([0, 0, 30, 8], fill=(255, 255, 0))
+        dm.update_display()   # push + snapshot write (first frame)
+        assert os.path.exists(dm._snapshot_path)
+        first_mtime = os.path.getmtime(dm._snapshot_path)
+
+        # Age the write/touch bookkeeping past TOUCH_INTERVAL so the next
+        # identical frame is due for a touch, then push it again: dirty
+        # tracking must skip the panel write, but the snapshot mirror must
+        # still get its mtime bumped so the health check doesn't go stale.
+        from src.common import snapshot_policy
+        stale_ts = time.time() - snapshot_policy.TOUCH_INTERVAL - 1.0
+        dm._last_snapshot_ts = stale_ts
+        dm._last_snapshot_touch_ts = stale_ts
+        with _SwapSpy(dm.matrix) as spy:
+            dm.update_display()  # identical frame -> panel push skipped
+        assert spy.count == 0
+        assert os.path.getmtime(dm._snapshot_path) > first_mtime
+
+
+class TestKillSwitch:
+    def test_dirty_tracking_can_be_disabled(self, dm):
+        dm._dirty_tracking_enabled = False
+        try:
+            dm.draw.rectangle([0, 0, 10, 10], fill=(1, 2, 3))
+            with _SwapSpy(dm.matrix) as spy:
+                dm.update_display()
+                dm.update_display()
+                dm.update_display()
+            assert spy.count == 3  # always-push, exactly the old behavior
+        finally:
+            dm._dirty_tracking_enabled = True
+            dm._last_pushed_digest = None
+
+    def test_config_flag_wires_through(self):
+        from src.display_manager import DisplayManager
+        DisplayManager._instance = None
+        DisplayManager._initialized = False
+        try:
+            manager = DisplayManager({
+                "display": {
+                    "hardware": {"rows": 32, "cols": 64, "chain_length": 1,
+                                 "parallel": 1},
+                    "runtime": {"gpio_slowdown": 0},
+                    "dirty_tracking": False,
+                },
+            }, suppress_test_pattern=True)
+            assert manager._dirty_tracking_enabled is False
+        finally:
+            DisplayManager._instance = None
+            DisplayManager._initialized = False
+
+
+if __name__ == "__main__":
+    sys.exit(pytest.main([__file__, "-v"]))

test/test_harness_fill.py

@@ -0,0 +1,98 @@
+"""Tests for the harness fill / scale-up check (src/plugin_system/testing/harness.py)."""
+
+from PIL import Image
+
+from src.plugin_system.testing.harness import (
+    RenderResult,
+    check_scale_up,
+    fill_metrics,
+)
+
+
+def _canvas(w, h):
+    return Image.new("RGB", (w, h), (0, 0, 0))
+
+
+def _with_block(w, h, bx, by, bw, bh, color=(255, 255, 255)):
+    img = _canvas(w, h)
+    img.paste(Image.new("RGB", (bw, bh), color), (bx, by))
+    return img
+
+
+def _result(w, h, image):
+    return RenderResult("p", w, h, "mode", image=image)
+
+
+class TestFillMetrics:
+    def test_full_white(self):
+        ex, ey, ink = fill_metrics(Image.new("RGB", (64, 32), (255, 255, 255)))
+        assert (ex, ey, ink) == (1.0, 1.0, 1.0)
+
+    def test_black_is_empty(self):
+        assert fill_metrics(_canvas(64, 32)) == (0.0, 0.0, 0.0)
+
+    def test_corner_dot(self):
+        ex, ey, ink = fill_metrics(_with_block(100, 100, 0, 0, 10, 10))
+        assert ex == 0.1 and ey == 0.1
+        assert ink == 0.01
+
+    def test_centered_half(self):
+        ex, ey, _ = fill_metrics(_with_block(100, 100, 25, 25, 50, 50))
+        assert ex == 0.5 and ey == 0.5
+
+    def test_dim_pixels_ignored(self):
+        img = _canvas(10, 10)
+        img.putpixel((5, 5), (10, 10, 10))  # below the lit threshold
+        assert fill_metrics(img) == (0.0, 0.0, 0.0)
+
+
+class TestCheckScaleUp:
+    def test_not_checked_below_2x(self):
+        # 128x64 vs design 128x32: only height is 2x -> checked on y only;
+        # 128x32 itself: not checked at all
+        r = _result(128, 32, _with_block(128, 32, 0, 0, 10, 10))
+        check_scale_up([r], design_size=(128, 32))
+        assert not r.fill_checked
+
+    def test_warn_mode_records_but_passes(self):
+        # tiny corner content on a 256x128 (2x both axes)
+        r = _result(256, 128, _with_block(256, 128, 0, 0, 20, 20))
+        check_scale_up([r], design_size=(128, 32), strict=False)
+        assert r.fill_checked
+        assert r.fill_ok is None       # warn-only: not a failure
+        assert r.ok                    # still passes
+        assert r.fill_extent[0] < 0.5
+
+    def test_strict_mode_fails_underfill(self):
+        r = _result(256, 128, _with_block(256, 128, 0, 0, 20, 20))
+        check_scale_up([r], design_size=(128, 32), strict=True)
+        assert r.fill_ok is False
+        assert not r.ok
+
+    def test_well_filled_passes_strict(self):
+        r = _result(256, 128, _with_block(256, 128, 10, 10, 200, 100))
+        check_scale_up([r], design_size=(128, 32), strict=True)
+        assert r.fill_ok is True and r.ok
+
+    def test_axis_selection_wide_only(self):
+        # 256x32 vs design 128x32: width is 2x, height is not -> only the
+        # x-extent matters; content spanning full width but few rows passes
+        r = _result(256, 32, _with_block(256, 32, 0, 12, 250, 8))
+        check_scale_up([r], design_size=(128, 32), strict=True)
+        assert r.fill_ok is True
+
+    def test_axis_selection_wide_only_underfill(self):
+        r = _result(256, 32, _with_block(256, 32, 0, 12, 60, 8))
+        check_scale_up([r], design_size=(128, 32), strict=True)
+        assert r.fill_ok is False
+
+    def test_errored_render_skipped(self):
+        r = RenderResult("p", 256, 128, "m", error="boom")
+        check_scale_up([r], design_size=(128, 32), strict=True)
+        assert not r.fill_checked
+
+    def test_custom_design_size(self):
+        # 128x64 with design 64x32 IS 2x both axes
+        r = _result(128, 64, _with_block(128, 64, 0, 0, 10, 10))
+        check_scale_up([r], design_size=(64, 32), strict=False)
+        assert r.fill_checked

test/test_loader_compat_warning.py

@@ -0,0 +1,70 @@
+"""Tests for the plugin loader's advisory version-compatibility warning."""
+
+import logging
+
+import pytest
+
+from src.plugin_system.plugin_loader import PluginLoader
+
+
+@pytest.fixture
+def loader():
+    return PluginLoader(logger=logging.getLogger("test-loader"))
+
+
+def _warnings(caplog):
+    return [r for r in caplog.records if r.levelno == logging.WARNING]
+
+
+class TestParseSemver:
+    def test_basic(self, loader):
+        assert loader._parse_semver("3.1.0") == (3, 1, 0)
+        assert loader._parse_semver("v2.0") == (2, 0, 0)
+        assert loader._parse_semver("2.0.0-beta.1") == (2, 0, 0)
+
+    def test_unparseable(self, loader):
+        assert loader._parse_semver(None) is None
+        assert loader._parse_semver(123) is None
+
+
+class TestWarnIfIncompatible:
+    def test_warns_when_plugin_needs_newer_core(self, loader, caplog, monkeypatch):
+        import src
+        monkeypatch.setattr(src, "__version__", "3.1.0")
+        with caplog.at_level(logging.WARNING, logger="test-loader"):
+            loader._warn_if_incompatible("p", {"min_ledmatrix_version": "9.0.0"})
+        assert len(_warnings(caplog)) == 1
+        assert "9.0.0" in _warnings(caplog)[0].message
+
+    def test_silent_when_compatible(self, loader, caplog, monkeypatch):
+        import src
+        monkeypatch.setattr(src, "__version__", "3.1.0")
+        with caplog.at_level(logging.WARNING, logger="test-loader"):
+            loader._warn_if_incompatible("p", {"min_ledmatrix_version": "2.0.0"})
+        assert not _warnings(caplog)
+
+    def test_silent_when_field_absent(self, loader, caplog):
+        with caplog.at_level(logging.WARNING, logger="test-loader"):
+            loader._warn_if_incompatible("p", {"name": "no version fields"})
+        assert not _warnings(caplog)
+
+    def test_reads_requires_and_versions_spellings(self, loader, caplog, monkeypatch):
+        import src
+        monkeypatch.setattr(src, "__version__", "3.1.0")
+        with caplog.at_level(logging.WARNING, logger="test-loader"):
+            loader._warn_if_incompatible(
+                "a", {"requires": {"min_ledmatrix_version": "9.0.0"}})
+            loader._warn_if_incompatible(
+                "b", {"versions": [{"ledmatrix_min_version": "9.0.0"}]})
+            loader._warn_if_incompatible(
+                "c", {"versions": [{"ledmatrix_min": "9.0.0"}]})
+        assert len(_warnings(caplog)) == 3
+
+    def test_stale_core_version_skips_comparison(self, loader, caplog, monkeypatch):
+        # Anti-spam guard: a core whose __version__ is below the ecosystem
+        # floor must not warn about every plugin.
+        import src
+        monkeypatch.setattr(src, "__version__", "1.0.0")
+        with caplog.at_level(logging.WARNING, logger="test-loader"):
+            loader._warn_if_incompatible("p", {"min_ledmatrix_version": "2.0.0"})
+        assert not _warnings(caplog)

test/test_permission_utils.py

@@ -0,0 +1,83 @@
+"""
+Tests for src.common.permission_utils's URL-credential redaction.
+
+Covers the fix for a CodeQL clear-text-logging-of-secrets alert:
+install_requirements_file() must never let a private index URL's embedded
+user:pass@ credentials reach logs or its returned CompletedProcess, since
+pip can echo that URL back verbatim in its own stderr/stdout on failure.
+"""
+
+from pathlib import Path
+from unittest.mock import MagicMock, patch
+
+from src.common.permission_utils import _redact_url_credentials, install_requirements_file
+
+
+class TestRedactUrlCredentials:
+    def test_redacts_embedded_basic_auth(self):
+        text = "Could not fetch URL https://alice:s3cr3t@pypi.example.com/simple/: 403"
+        redacted = _redact_url_credentials(text)
+        assert "s3cr3t" not in redacted
+        assert "alice" not in redacted
+        assert "https://***:***@pypi.example.com/simple/" in redacted
+
+    def test_leaves_credential_free_text_unchanged(self):
+        text = "ERROR: Could not find a version that satisfies the requirement foo==1.0"
+        assert _redact_url_credentials(text) == text
+
+    def test_handles_none_and_empty(self):
+        assert _redact_url_credentials(None) == ""
+        assert _redact_url_credentials("") == ""
+
+    def test_does_not_touch_denied_check_phrases(self):
+        """The fixed phrases install_requirements_file greps for must survive
+        redaction untouched -- they don't overlap with URL syntax, but this
+        pins that assumption so a regex change can't silently break it."""
+        text = "sudo: a password is required"
+        assert _redact_url_credentials(text) == text
+
+
+class TestInstallRequirementsFileRedaction:
+    @patch('src.common.permission_utils.subprocess.run')
+    def test_wrapper_path_redacts_stderr_and_stdout(self, mock_run, tmp_path):
+        """safe_pip_install.sh exists in this repo, so install_requirements_file
+        takes the sudo-wrapper branch; a failing result must come back
+        with any embedded index-URL credentials already redacted."""
+        req_file = tmp_path / "requirements.txt"
+        req_file.write_text("requests\n")
+
+        mock_run.return_value = MagicMock(
+            returncode=1,
+            stdout="Looking in indexes: https://bob:hunter2@pypi.internal/simple\n",
+            stderr="ERROR https://bob:hunter2@pypi.internal/simple/foo: 401",
+        )
+
+        result = install_requirements_file(req_file, timeout=5)
+
+        assert "hunter2" not in result.stdout
+        assert "hunter2" not in result.stderr
+        assert "https://***:***@pypi.internal" in result.stdout
+        assert "https://***:***@pypi.internal" in result.stderr
+
+    @patch('src.common.permission_utils.subprocess.run')
+    @patch('src.common.permission_utils.Path.exists', return_value=False)
+    def test_no_wrapper_fallback_path_redacts_stderr_and_stdout(self, mock_exists, mock_run, tmp_path):
+        """No safe_pip_install.sh wrapper -> falls straight to the
+        sys.executable pip fallback (the second subprocess.run call site);
+        its result must come back redacted too, independent of the wrapper
+        branch's own redaction above."""
+        req_file = tmp_path / "requirements.txt"
+        req_file.write_text("requests\n")
+
+        mock_run.return_value = MagicMock(
+            returncode=1,
+            stdout="Looking in indexes: https://carol:swordfish@pypi.internal/simple\n",
+            stderr="ERROR https://carol:swordfish@pypi.internal/simple/foo: 401",
+        )
+
+        result = install_requirements_file(req_file, timeout=5)
+
+        assert "swordfish" not in result.stdout
+        assert "swordfish" not in result.stderr
+        assert "https://***:***@pypi.internal" in result.stdout
+        assert "https://***:***@pypi.internal" in result.stderr

test/test_plugin_health.py

@@ -0,0 +1,93 @@
+"""
+Tests for src/plugin_system/plugin_health.py
+
+Focus on the additive ``set_degraded`` mechanism used by the warn-only schema
+validation path: it must surface a degraded reason without touching the circuit
+breaker or causing the plugin to be skipped.
+"""
+
+from unittest.mock import MagicMock
+
+from src.plugin_system.plugin_health import PluginHealthTracker, CircuitState
+
+
+def _cache():
+    cache = MagicMock()
+    cache.get.return_value = None
+    return cache
+
+
+def test_set_degraded_marks_and_surfaces_reason():
+    tracker = PluginHealthTracker(_cache())
+    tracker.set_degraded("p", "bad config")
+    summary = tracker.get_health_summary("p")
+    assert summary["degraded"] is True
+    assert summary["degraded_reason"] == "bad config"
+
+
+def test_set_degraded_none_clears():
+    tracker = PluginHealthTracker(_cache())
+    tracker.set_degraded("p", "bad config")
+    tracker.set_degraded("p", None)
+    summary = tracker.get_health_summary("p")
+    assert summary["degraded"] is False
+    assert summary["degraded_reason"] is None
+
+
+def test_set_degraded_does_not_affect_circuit_breaker():
+    tracker = PluginHealthTracker(_cache())
+    tracker.set_degraded("p", "bad config")
+    summary = tracker.get_health_summary("p")
+    # Degraded is a *separate* signal from circuit health: the plugin is not
+    # counted as failing, the circuit stays closed, and it is not skipped.
+    assert summary["circuit_state"] == CircuitState.CLOSED.value
+    assert summary["consecutive_failures"] == 0
+    assert summary["is_healthy"] is True
+    assert tracker.should_skip_plugin("p") is False
+
+
+def test_set_degraded_skips_redundant_cache_write():
+    cache = _cache()
+    tracker = PluginHealthTracker(cache)
+    tracker.set_degraded("p", "x")
+    writes_after_first = cache.set.call_count
+    assert writes_after_first >= 1
+    tracker.set_degraded("p", "x")  # unchanged → no extra write
+    assert cache.set.call_count == writes_after_first
+
+
+def test_default_summary_has_degraded_fields():
+    tracker = PluginHealthTracker(_cache())
+    summary = tracker.get_health_summary("never-seen")
+    assert summary["degraded"] is False
+    assert summary["degraded_reason"] is None
+
+
+def test_force_reload_refreshes_stale_in_memory_snapshot():
+    """A long-lived reader (e.g. the web process) must not be pinned to the
+    first snapshot: force_reload re-reads persisted state and bypasses the
+    cache manager's memory tier so cross-process updates are visible."""
+    cache = _cache()
+    tracker = PluginHealthTracker(cache)
+
+    # First read snapshots an empty (healthy) state into the in-memory copy.
+    assert tracker.get_health_summary("p")["consecutive_failures"] == 0
+
+    # The display service later persists a failing/open state.
+    cache.get.return_value = {
+        "consecutive_failures": 5,
+        "circuit_state": "open",
+        "total_failures": 5,
+        "total_successes": 0,
+    }
+
+    # A plain read is still pinned to the stale snapshot...
+    assert tracker.get_health_summary("p")["consecutive_failures"] == 0
+
+    # ...but force_reload observes the new persisted state.
+    fresh = tracker.get_health_summary("p", force_reload=True)
+    assert fresh["consecutive_failures"] == 5
+    assert fresh["circuit_state"] == "open"
+
+    # and it asked the cache to bypass the in-memory tier (memory_ttl=0).
+    assert any(c.kwargs.get("memory_ttl") == 0 for c in cache.get.call_args_list)