Feature/vegas scroll mode (#215)

* feat(display): add Vegas-style continuous scroll mode

Implement an opt-in Vegas ticker mode that composes all enabled plugin
content into a single continuous horizontal scroll. Includes a modular
package (src/vegas_mode/) with double-buffered streaming, 125 FPS
render pipeline using the existing ScrollHelper, live priority
interruption support, and a web UI for configuration with drag-drop
plugin ordering.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* feat(vegas): add three-mode display system (SCROLL, FIXED_SEGMENT, STATIC)

Adds a flexible display mode system for Vegas scroll mode that allows
plugins to control how their content appears in the continuous scroll:

- SCROLL: Content scrolls continuously (multi-item plugins like sports)
- FIXED_SEGMENT: Fixed block that scrolls by (clock, weather)
- STATIC: Scroll pauses, plugin displays, then resumes (alerts)

Changes:
- Add VegasDisplayMode enum to base_plugin.py with backward-compatible
  mapping from legacy get_vegas_content_type()
- Add static pause handling to coordinator with scroll position save/restore
- Add mode-aware content composition to stream_manager
- Add vegas_mode info to /api/v3/plugins/installed endpoint
- Add mode indicators to Vegas settings UI
- Add comprehensive plugin developer documentation

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix(vegas,widgets): address validation, thread safety, and XSS issues

Vegas mode fixes:
- config.py: align validation limits with UI (scroll_speed max 200, separator_width max 128)
- coordinator.py: fix race condition by properly initializing _pending_config
- plugin_adapter.py: remove unused import
- render_pipeline.py: preserve deque type in reset() method
- stream_manager.py: fix lock handling and swap_buffers to truly swap

API fixes:
- api_v3.py: normalize boolean checkbox values, validate numeric fields, ensure JSON arrays

Widget fixes:
- day-selector.js: remove escapeHtml from JSON.stringify to prevent corruption
- password-input.js: use deterministic color class mapping for Tailwind JIT
- radio-group.js: replace inline onchange with addEventListener to prevent XSS
- select-dropdown.js: guard global registry access
- slider.js: add escapeAttr for attributes, fix null dereference in setValue

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix(vegas): improve exception handling and static pause state management

coordinator.py:
- _check_live_priority: use logger.exception for full traceback
- _end_static_pause: guard scroll resume on interruption (stop/live priority)
- _update_static_mode_plugins: log errors instead of silently swallowing

render_pipeline.py:
- compose_scroll_content: use specific exceptions and logger.exception
- render_frame: use specific exceptions and logger.exception
- hot_swap_content: use specific exceptions and logger.exception

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix(vegas): add interrupt mechanism and improve config/exception handling

- Add interrupt checker callback to Vegas coordinator for responsive
  handling of on-demand requests and wifi status during Vegas mode
- Fix config.py update() to include dynamic duration fields
- Fix is_plugin_included() consistency with get_ordered_plugins()
- Update _apply_pending_config to propagate config to StreamManager
- Change _fetch_plugin_content to use logger.exception for traceback
- Replace bare except in _refresh_plugin_list with specific exceptions
- Add aria-label accessibility to Vegas toggle checkbox
- Fix XSS vulnerability in plugin metadata rendering with escapeHtml

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix(vegas): improve logging, validation, lock handling, and config updates

- display_controller.py: use logger.exception for Vegas errors with traceback
- base_plugin.py: validate vegas_panel_count as positive integer with warning
- coordinator.py: fix _apply_pending_config to avoid losing concurrent updates
  by clearing _pending_config while holding lock
- plugin_adapter.py: remove broad catch-all, use narrower exception types
  (AttributeError, TypeError, ValueError, OSError, RuntimeError) and
  logger.exception for traceback preservation
- api_v3.py: only update vegas_config['enabled'] when key is present in data
  to prevent incorrect disabling when checkbox is omitted

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix(vegas): improve cycle advancement, logging, and accessibility

- Add advance_cycle() method to StreamManager for clearing buffer between cycles
- Call advance_cycle() in RenderPipeline.start_new_cycle() for fresh content
- Use logger.exception() for interrupt check and static pause errors (full tracebacks)
- Add id="vegas_scroll_label" to h3 for aria-labelledby reference
- Call updatePluginConfig() after rendering plugin list for proper initialization

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix(vegas): add thread-safety, preserve updates, and improve logging

- display_controller.py: Use logger.exception() for Vegas import errors
- plugin_adapter.py: Add thread-safe cache lock, remove unused exception binding
- stream_manager.py: In-place merge in process_updates() preserves non-updated plugins
- api_v3.py: Change vegas_scroll_enabled default from False to True

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix(vegas): add debug logging and narrow exception types

- stream_manager.py: Log when get_vegas_display_mode() is unavailable
- stream_manager.py: Narrow exception type from Exception to (AttributeError, TypeError)
- api_v3.py: Log exceptions when reading Vegas display metadata with plugin context

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix(vegas): fix method call and improve exception logging

- Fix _check_vegas_interrupt() calling nonexistent _check_wifi_status(),
  now correctly calls _check_wifi_status_message()
- Update _refresh_plugin_list() exception handler to use logger.exception()
  with plugin_id and class name for remote debugging

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix(web): replace complex toggle with standard checkbox for Vegas mode

The Tailwind pseudo-element toggle (after:content-[''], etc.) wasn't
rendering because these classes weren't in the CSS bundle. Replaced
with a simple checkbox that matches other form controls in the template.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* debug(vegas): add detailed logging to _refresh_plugin_list

Track why plugins aren't being found for Vegas scroll:
- Log count of loaded plugins
- Log enabled status for each plugin
- Log content_type and display_mode checks
- Log when plugin_manager lacks loaded_plugins

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix(vegas): use correct attribute name for plugin manager

StreamManager and VegasModeCoordinator were checking for
plugin_manager.loaded_plugins but PluginManager stores active
plugins in plugin_manager.plugins. This caused Vegas scroll
to find zero plugins despite plugins being available.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix(vegas): convert scroll_speed from px/sec to px/frame correctly

The config scroll_speed is in pixels per second, but ScrollHelper
in frame_based_scrolling mode interprets it as pixels per frame.
Previously this caused the speed to be clamped to max 5.0 regardless
of the configured value.

Now properly converts: pixels_per_frame = scroll_speed * scroll_delay

With defaults (50 px/s, 0.02s delay), this gives 1 px/frame = 50 px/s.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* feat(vegas): add FPS logging every 5 seconds

Logs actual FPS vs target FPS to help diagnose performance issues.
Shows frame count in each 5-second interval.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix(vegas): improve plugin content capture reliability

- Call update_data() before capture to ensure fresh plugin data
- Try display() without force_clear first, fallback if TypeError
- Retry capture with force_clear=True if first attempt is blank
- Use histogram-based blank detection instead of point sampling
  (more reliable for content positioned anywhere in frame)

This should help capture content from plugins that don't implement
get_vegas_content() natively.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix(vegas): handle callable width/height on display_manager

DisplayManager.width and .height may be methods or properties depending
on the implementation. Use callable() check to call them if needed,
ensuring display_width and display_height are always integers.

Fixes potential TypeError when width/height are methods.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix(vegas): use logger.exception for display mode errors

Replace logger.error with logger.exception to capture full stack trace
when get_vegas_display_mode() fails on a plugin.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix(vegas): protect plugin list updates with buffer lock

Move assignment of _ordered_plugins and index resets under _buffer_lock
to prevent race conditions with _prefetch_content() which reads these
variables under the same lock.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix(vegas): catch all exceptions in get_vegas_display_mode

Broaden exception handling from AttributeError/TypeError to Exception
so any plugin error in get_vegas_display_mode() doesn't abort the
entire plugin list refresh. The loop continues with the default
FIXED_SEGMENT mode.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix(vegas): refresh stream manager when config updates

After updating stream_manager.config, force a refresh to pick up changes
to plugin_order, excluded_plugins, and buffer_ahead settings. Also use
logger.exception to capture full stack traces on config update errors.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* debug(vegas): add detailed logging for blank image detection

* feat(vegas): extract full scroll content from plugins using ScrollHelper

Plugins like ledmatrix-stocks and odds-ticker use ScrollHelper with a
cached_image that contains their full scrolling content. Instead of
falling back to single-frame capture, now check for scroll_helper.cached_image
first to get the complete scrolling content for Vegas mode.

* debug(vegas): add comprehensive INFO-level logging for plugin content flow

- Log each plugin being processed with class name
- Log which content methods are tried (native, scroll_helper, fallback)
- Log success/failure of each method with image dimensions
- Log brightness check results for blank image detection
- Add visual separators in logs for easier debugging
- Log plugin list refresh with enabled/excluded status

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* feat(vegas): trigger scroll content generation when cache is empty

When a plugin has a scroll_helper but its cached_image is not yet
populated, try to trigger content generation by:
1. Calling _create_scrolling_display() if available (stocks pattern)
2. Calling display(force_clear=True) as a fallback

This allows plugins like stocks to provide their full scroll content
even when Vegas mode starts before the plugin has run its normal
display cycle.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix: improve exception handling in plugin_adapter scroll content retrieval

Replace broad except Exception handlers with narrow exception types
(AttributeError, TypeError, ValueError, OSError) and use logger.exception
instead of logger.warning/info to capture full stack traces for better
diagnosability.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix: narrow exception handling in coordinator and plugin_adapter

- coordinator.py: Replace broad Exception catch around get_vegas_display_mode()
  with (AttributeError, TypeError) and use logger.exception for stack traces
- plugin_adapter.py: Narrow update_data() exception handler to
  (AttributeError, RuntimeError, OSError) and use logger.exception

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix: improve Vegas mode robustness and API validation

- display_controller: Guard against None plugin_manager in Vegas init
- coordinator: Restore scrolling state in resume() to match pause()
- api_v3: Validate Vegas numeric fields with range checks and 400 errors

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

---------

Co-authored-by: Chuck <chuck@example.com>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

config/config.template.json

@@ -72,7 +72,16 @@
         "display_durations": {
             "calendar": 30
         },
-        "use_short_date_format": true
+        "use_short_date_format": true,
+        "vegas_scroll": {
+            "enabled": false,
+            "scroll_speed": 50,
+            "separator_width": 32,
+            "plugin_order": [],
+            "excluded_plugins": [],
+            "target_fps": 125,
+            "buffer_ahead": 2
+        }
     },
     "plugin_system": {
         "plugins_directory": "plugin-repos",