fix(fonts): load 4x6 on its pixel grid, from any working directory (#565)

* fix(fonts): load 4x6 on its pixel grid, from any working directory

`extra_small_font` loaded 4x6-font.ttf at 6, off the face's 7px grid.
Under `draw.fontmode = "1"` the mono rasteriser thresholds each glyph at
50% coverage, so every glyph lost its fourth column and deformed:
christmas-countdown rendered "UNTIL" as "VM1JL". The advance is 5px at
both sizes, so snapping to 7 reflows nothing.

- Sizes in DisplayManager._load_fonts go through crisp_size() instead of
  literals. crisp_size / FONT_PIXEL_GRID / FONT_NAME_ALIASES move to
  src/common/font_layout.py; sports_card re-exports them.
- Mirror the fix in VisualTestDisplayManager, the harness's fork of
  _load_fonts. Without it every golden is blessed at the old size.
- Resolve bundled font paths against the install root, not the cwd.
  FontManager._resolve_asset_path now delegates to
  font_layout.resolve_asset_path (kept by name; plugins probe for it).
- The startup banner's middle rung snaps to 7; the 5 rung stays off-grid
  on purpose (the only size that fits a dotted quad on 64px).
- loading.py reads all plugin JSON as UTF-8 (cp1252 on Windows aborted
  check_plugin.py on a 0x9d byte).
- check_plugin.py reports in ASCII and never dies on an unencodable char.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(fonts): resolve relative asset paths from the install root, not the cwd

resolve_asset_path checked os.path.exists(relative_path) unconditionally,
so a relative asset path was still resolved against the process cwd first
-- exactly the dependency this module exists to remove. An unrelated
working directory that happens to contain assets/fonts/4x6-font.ttf (a
stale checkout, a copied assets folder, another project) would shadow the
real bundled font instead of the install root ever being consulted.

Only an absolute path is now returned as-is; a relative path always
resolves against _INSTALL_ROOT first, matching the docstring's stated
contract. FontManager._resolve_asset_path delegates to this function, so
it's covered by the same fix.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

src/plugin_system/testing/visual_display_manager.py

@@ -31,7 +31,7 @@ from pathlib import Path
 from typing import Any, List, Optional, Tuple
 
 from PIL import Image, ImageDraw, ImageFont
-from src.common.font_layout import load_truetype
+from src.common.font_layout import crisp_size, load_truetype
 
 from src.logging_config import get_logger
 
@@ -141,9 +141,10 @@ class VisualTestDisplayManager:
             fonts_dir = project_root / 'assets' / 'fonts'
 
             # Press Start 2P — regular and small (both 8px)
-            ttf_path = str(fonts_dir / 'PressStart2P-Regular.ttf')
-            self.regular_font = load_truetype(ttf_path, 8)
-            self.small_font = load_truetype(ttf_path, 8)
+            press_start = 'PressStart2P-Regular.ttf'
+            ttf_path = str(fonts_dir / press_start)
+            self.regular_font = load_truetype(ttf_path, crisp_size(press_start, 8))
+            self.small_font = load_truetype(ttf_path, crisp_size(press_start, 8))
             self.font = self.regular_font  # alias used by some code paths
 
             # 5x7 BDF font via freetype
@@ -160,10 +161,15 @@ class VisualTestDisplayManager:
                 self.calendar_font = self.small_font
                 self.bdf_5x7_font = self.small_font
 
-            # 4x6 extra small TTF
+            # 4x6 extra small TTF, snapped to the face's 7px grid exactly as
+            # DisplayManager._load_fonts does. Sizing this independently is how
+            # the harness would render -- and bless goldens -- in a face the
+            # panel never uses: at the off-grid 6 this asked for, every glyph
+            # loses its fourth column under `draw.fontmode = "1"`.
             try:
-                xs_path = str(fonts_dir / '4x6-font.ttf')
-                self.extra_small_font = load_truetype(xs_path, 6)
+                four_by_six = '4x6-font.ttf'
+                xs_path = str(fonts_dir / four_by_six)
+                self.extra_small_font = load_truetype(xs_path, crisp_size(four_by_six, 6))
             except (FileNotFoundError, OSError) as e:
                 logger.debug("Extra small font not available, using fallback: %s", e)
                 self.extra_small_font = self.small_font