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

web_interface/templates/v3/partials/display.html

@@ -556,11 +556,11 @@
                         </div>
 
                         <div class="form-group" id="setting-display-vegas_max_plugin_width_ratio" data-setting-key="display.vegas_scroll.max_plugin_width_ratio">
-                            <label for="vegas_max_plugin_width_ratio" class="block text-sm font-medium text-gray-700">Max Plugin Width (screens){{ ui.help_tip('Caps how much of one cycle a single plugin may occupy, measured in screen widths (0–20).\nDefault: 3. A long ticker such as a news feed or leaderboard is trimmed to this and the remainder shown on later cycles, so one plugin cannot hold the display for minutes. Set 0 for no limit.', 'Max Plugin Width') }}</label>
+                            <label for="vegas_max_plugin_width_ratio" class="block text-sm font-medium text-gray-700">Max Plugin Width (screens){{ ui.help_tip('Caps how much of one cycle a single plugin may occupy, measured in screen widths (0–20).\nDefault: 0 (no limit) — every plugin shows all of its content and always starts at the beginning.\nSet a limit to stop one long ticker holding the display for minutes: it is cut to this width and the remainder shown on later cycles. The trade-off is that such a plugin then resumes mid-content on each appearance instead of starting fresh.', 'Max Plugin Width') }}</label>
                             <input type="number"
                                    id="vegas_max_plugin_width_ratio"
                                    name="vegas_max_plugin_width_ratio"
-                                   value="{{ main_config.display.get('vegas_scroll', {}).get('max_plugin_width_ratio', 3.0) }}"
+                                   value="{{ main_config.display.get('vegas_scroll', {}).get('max_plugin_width_ratio', 0.0) }}"
                                    min="0"
                                    max="20"
                                    step="0.5"