feat(sports): live Vegas cards for the scoreboards (shared layer) (#698)

* perf(timing): say which render-thread work a late frame followed

The soak already says how often a moving frame reached the panel late, but
not what the render thread was doing just before it. Vegas does two kinds of
work there between frames -- building its strip (compose, extend) and, with
live elements, patching changed pixels into it -- and deciding whether either
is affordable needs their own numbers.

- FrameTimingRecorder.note_op(kind, nbytes) tags the next presented frame.
  Totals gain op_frames, late_op_frames, op_freezes and op_bytes per kind;
  aggregate() still takes frames without ops. The file schema is unchanged.
- Vegas tags compose and every strip extension (with the bytes it copied).
- frame_soak prints an "after work" table: frames, late %, freezes and MB
  moved per kind, only when something tagged its work.
- render_bench gains --strip-screens (Vegas-sized strips), --patch-bytes /
  --patch-every / --patch-where (in-place column writes, as a live element
  update does) and --extend-every-screens / --extend-width (append + trim on
  a fixed cadence that holds the strip's width).

No runtime behaviour changes: this is the measurement gate for live Vegas
elements.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* docs(changelog): note the frame-op attribution and bench modes

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* perf(scroll): build the strip's PIL image only when something reads it

Every Vegas strip extension rebuilt ScrollHelper.cached_image from
cached_array in full, twice (append, then trim), on the render thread:
Image.fromarray is 1.7ms for an 8,000px strip and 3.8ms for 20,000px on a
Pi 4 (measured on ledpi), about two thirds of an extension's render-thread
cost. Nothing on the frame path reads the image's pixels; every frame is cut
from the array.

cached_image is now a property. append_content and drop_scrolled_prefix
defer it; the first read builds it from the array it started with and keeps
it only if the strip has not changed meanwhile, so a sync push racing an
extension cannot leave a stale image cached. Assigning cached_image stores
exactly what was assigned, as before. has_strip() says whether there is a
strip without building its image; the helper's frame path, Vegas and the
adapter's scroll-cache invalidation use it. The strip is also no longer held
in memory twice.

In Vegas the image is now built only by a multi-display sync push.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* feat(vegas): live elements -- a plugin API for content that changes while it scrolls

Vegas bakes each plugin's pictures into one strip, so a card already on its
way across the panel keeps what it showed when it was drawn. This adds the
API and bookkeeping for content that can be updated in place; the worker
that redraws and swaps it follows separately. No shipped plugin implements
the hook yet, so nothing changes for users.

Plugin API (core 3.8.0), all no-ops by default:
- BasePlugin.get_vegas_elements() -> [VegasElement(key, image, version,
  live, refresh_hz)]: named, fixed-width pieces of Vegas content.
- BasePlugin.redraw_vegas_element(key, width, height, at): a lock-free
  redraw for content that changes with time.
- BasePlugin.notify_vegas_data_changed(): data that lands outside update().
- src/plugin_system/vegas_elements.py (VegasElement, re-exported from
  base_plugin).

Core:
- PluginAdapter asks a plugin that implements the hook for elements on the
  background fetch only (under its lock, on its own canvas); every other
  path keeps get_vegas_content(). Live elements are pinned (padded with
  content_padding, never trimmed), tagged with their key, digest and data
  epoch in Image.info so the existing cache and group plumbing carry them
  unchanged, and untagged if a width budget crops them.
- RenderPipeline records where each live element lands (ElementRecord), in
  absolute strip columns a trim does not move; the block-start arithmetic
  is shared with the STATIC markers.
- PluginManager update listeners (add/remove_update_listener,
  notify_data_changed): told the moment update() completes, not at the
  next ~4s Vegas poll. The coordinator uses one to move each plugin's data
  epoch on.
- vegas_scroll.live_refresh (kill switch), live_max_hz, live_min_interval,
  live_lead_screens; per-plugin core-owned vegas_live. Live elements are
  off under multi-display sync, in swap mode and with offscreen_prefetch off.
- scripts/check_plugin.py checks the element contract
  (src/plugin_system/testing/vegas.py); test/fixtures/plugins/vegas-live-stub
  is a working example.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* feat(vegas): live elements update in place while they scroll

One background worker (src/vegas_mode/live_worker.py) redraws a plugin's
live elements when its data epoch moves on (update listener) or on their
refresh_hz, nearest the screen first, and hands changed pixels lock-free to
the render thread, which copies them into the strip between frames
(RenderPipeline.apply_live_patches, ScrollHelper.patch_columns): at most
four patches or two screens of bytes a frame, no drawing or locks there.
The worker takes over group prefetch once a live element is placed, runs
inside the render gate, and is supervised. Update tick 1s while live
elements exist. Web UI switch for live_refresh. OFFSCREEN_RENDERING.md
describes what was built and why SegmentStrip was not needed.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* feat(sports): live Vegas cards for the scoreboards (shared layer)

One live element per game, drawn only when what the card shows changes, so
a score changes on a card already crossing the panel. The shared part, so
each scoreboard adopts it in a few lines:

- src/common/sports_vegas.py: game_key, game_fingerprint (the whole game
  dict, frozen: no drawn field can be missed), dedupe_games, VegasCardCache,
  StickyOdds (odds a live poll left out stay drawn), finished_games /
  with_finished_games (a game that just went final keeps its card, after its
  league's live games; one a heuristic only judged over keeps its live
  state, so a tied end of regulation never shows FINAL early).
- SportsScrollDisplay.make_vegas_renderer() is the override point;
  build_vegas_elements() and SportsScrollDisplayManager
  .get_vegas_elements_for() do the rest. A card's version includes its
  teams' ranks, which the renderer draws from the rankings cache.
- SportsLiveSharedMixin._record_finished_game() / finished_games_snapshot():
  held for FINISHED_GAME_TTL after it leaves the live list.

A sport that does not implement make_vegas_renderer keeps its ordinary Vegas
content, so no scoreboard changes until it opts in.

scripts/render_plugin.py --vegas renders a plugin's Vegas block as the
ticker lays it out, and --timeline stacks it at successive moments as
the ticker would update it in place; the join is now
render_pipeline.join_plugin_rows().

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* refactor(sports): a default _determine_game_type on SportsScrollDisplay

render_vegas_card looked the method up with getattr and a None default, which
static analysis (Codacy) reports as calling something that may not be
callable. The base class now has the default -- the card type from the game's
state -- and the plugins that define their own override it as before.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* fix: review follow-ups on the shared live-card layer

- The reused Vegas renderer always gets the current rankings, empty
  included, so ranks cleared since are not kept drawn.
- render_plugin.py: --timeline refuses --no-live (a timeline shows live
  elements changing), --timeline/--no-live need --vegas, and the Vegas
  paths create the output's directory like the display path does.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

src/vegas_mode/render_pipeline.py

@@ -32,6 +32,51 @@ logger = logging.getLogger(__name__)
 SYNC_SEND_INTERVAL = 1.0 / 90
 
 
+def join_plugin_rows(
+    images: List[Image.Image], config: VegasModeConfig
+) -> Tuple[Image.Image, List[Tuple[int, ElementMeta, int]]]:
+    """Join one plugin's images into the block the strip will hold.
+
+    Returns ``(block, layout)``, layout being ``(x, meta, width)`` for every
+    image tagged as a live element (src/vegas_mode/elements.py), x measured
+    from the block's left edge. A single image is returned as it is.
+
+    A module function so tooling (scripts/render_plugin.py --vegas) lays a
+    plugin out exactly as the ticker does.
+    """
+    if len(images) == 1:
+        meta = meta_of(images[0])
+        layout = [(0, meta, images[0].width)] if meta is not None else []
+        return images[0], layout
+
+    floor = max(0, config.intra_plugin_gap)
+    target = max(0, config.min_content_separation)
+    threshold = config.trim_threshold
+
+    # Space by measured separation, not a flat gap. Rows drawn flush to their
+    # own edges (sports score cards) would otherwise end up nearly touching,
+    # while rows that already carry wide margins would be pushed needlessly
+    # further apart.
+    gaps = [
+        separation_gap(images[i], images[i + 1], target, floor, threshold)
+        for i in range(len(images) - 1)
+    ]
+
+    width = sum(img.width for img in images) + sum(gaps)
+    height = max(img.height for img in images)
+
+    block = Image.new('RGB', (width, height), (0, 0, 0))
+    layout: List[Tuple[int, ElementMeta, int]] = []
+    x = 0
+    for i, img in enumerate(images):
+        block.paste(img, (x, 0))
+        meta = meta_of(img)
+        if meta is not None:
+            layout.append((x, meta, img.width))
+        x += img.width + (gaps[i] if i < len(gaps) else 0)
+    return block, layout
+
+
 class RenderPipeline:
     """
     High-performance render pipeline for Vegas scroll mode.
@@ -787,42 +832,9 @@ class RenderPipeline:
     ) -> Tuple[Image.Image, List[Tuple[int, ElementMeta, int]]]:
         """_join_plugin_rows, plus where each live element landed in the block.
 
-        Returns ``(block, layout)``, layout being ``(x, meta, width)`` for
-        every image tagged as a live element (src/vegas_mode/elements.py), x
-        measured from the block's left edge. The offsets were always computed
-        here; they used to be thrown away.
+        See join_plugin_rows.
         """
-        if len(images) == 1:
-            meta = meta_of(images[0])
-            layout = [(0, meta, images[0].width)] if meta is not None else []
-            return images[0], layout
-
-        floor = max(0, self.config.intra_plugin_gap)
-        target = max(0, self.config.min_content_separation)
-        threshold = self.config.trim_threshold
-
-        # Space by measured separation, not a flat gap. Rows drawn flush to
-        # their own edges (sports score cards) would otherwise end up nearly
-        # touching, while rows that already carry wide margins would be pushed
-        # needlessly further apart.
-        gaps = [
-            separation_gap(images[i], images[i + 1], target, floor, threshold)
-            for i in range(len(images) - 1)
-        ]
-
-        width = sum(img.width for img in images) + sum(gaps)
-        height = max(img.height for img in images)
-
-        block = Image.new('RGB', (width, height), (0, 0, 0))
-        layout: List[Tuple[int, ElementMeta, int]] = []
-        x = 0
-        for i, img in enumerate(images):
-            block.paste(img, (x, 0))
-            meta = meta_of(img)
-            if meta is not None:
-                layout.append((x, meta, img.width))
-            x += img.width + (gaps[i] if i < len(gaps) else 0)
-        return block, layout
+        return join_plugin_rows(images, self.config)
 
     # -- live element records ---------------------------------------------
     #