fix(vegas): stop capping plugin width by default (#445)

* fix(vegas): stop capping plugin width by default

Vegas plugins read as "cut off early" or "starting in the middle". That
was the per-plugin width budget, not the scroll engine:
overflow_mode=rotate is designed to resume mid-content on each
appearance, so the symptom was the feature working as specified.

Measured over a 17-plugin fleet on a 512px panel, the cap was a bad
trade. Only four plugins were ever wide enough to hit the 3.0 default --
leaderboard 11,518px, news 10,021px, odds-ticker 4,643px, hockey
1,508px. Weather is 650px and flights 512px; the cap never touched them
or the other eleven. So it bought nothing on thirteen plugins while
costing two visible faults on four: content entering mid-item (a news
ticker started at column 6027 of its own strip), and a final rotation
window of whatever happened to be left -- 348px of an 1,840px stocks
ticker, seven seconds of panel time.

Default max_plugin_width_ratio to 0 (uncapped), so every plugin
contributes all of its content and is always entered at its beginning.
The cap remains available, and vegas_max_width_screens still caps an
individual plugin -- which is where the knob belongs, since a genuinely
long ticker is a property of that plugin rather than of the fleet.

Verified on a live 512px device: 327 budget crops in the preceding six
hours, none after.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Udr6MfaFLUPhX5Fgo67Jf5

* test(vegas): cover the width cap still working when asked for

Defaulting the cap off must not quietly remove it. Asserts that an
explicit ratio is honoured and validates, alongside the existing check
that omitting it means uncapped.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Udr6MfaFLUPhX5Fgo67Jf5

---------

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/vegas_mode/config.py

@@ -104,10 +104,22 @@ class VegasModeConfig:
     overflow_mode: str = "rotate"
 
     # Cap on one plugin's share of a cycle, as a multiple of display width.
-    # A single ticker returning 7,000px would otherwise hold the panel for over
-    # two minutes. Overflow is deferred to later cycles rather than discarded.
-    # 0 disables the cap.
-    max_plugin_width_ratio: float = 3.0
+    # 0 (the default) disables the cap, so every plugin contributes all of its
+    # content and is always entered at its beginning.
+    #
+    # Capping was the default until it proved to cost more than it bought.
+    # Measured over a 17-plugin fleet on a 512px panel, only four plugins were
+    # ever wide enough to hit a 3.0 cap; for those four it produced two visible
+    # faults. Content resumed mid-item on each appearance (a news ticker entered
+    # at column 6027 of its own strip), and the final window of a rotation was
+    # whatever happened to be left — 348px of a 1840px stocks ticker, seven
+    # seconds of panel time. Both read as the display being broken rather than
+    # as deferral working.
+    #
+    # A wide plugin does hold the panel for a long time uncapped: set the cap
+    # per plugin with vegas_max_width_screens where that matters, rather than
+    # globally where it mostly hurts plugins that were never the problem.
+    max_plugin_width_ratio: float = 0.0
 
     # Plugin management
     plugin_order: List[str] = field(default_factory=list)
@@ -159,7 +171,7 @@ class VegasModeConfig:
             lead_in_width=int(vegas_config.get('lead_in_width', 0)),
             plugins_per_cycle=int(vegas_config.get('plugins_per_cycle', 6)),
             max_plugin_width_ratio=float(
-                vegas_config.get('max_plugin_width_ratio', 3.0)),
+                vegas_config.get('max_plugin_width_ratio', 0.0)),
             overflow_mode=str(vegas_config.get('overflow_mode', 'rotate')),
             plugin_order=list(vegas_config.get('plugin_order', [])),
             excluded_plugins=set(vegas_config.get('excluded_plugins', [])),