Optimize KC processing and add reactive HAOS state updates

- Optimize KC frame processing: downsample to 160x90 with cv2.resize
  before rectangle extraction, pre-compute pixel coords, vectorize
  smoothing with numpy arrays
- Add WebSocket event stream for server state changes: processor manager
  fires events on start/stop, new /api/v1/events/ws endpoint streams
  them to connected clients
- Add HAOS EventStreamListener that triggers coordinator refresh on
  state changes for near-instant switch updates
- Reduce HAOS polling interval from 10s to 3s for fresher FPS metrics
- Fix overlay button tooltips: flatten nested JSON keys in locale files
  to match flat dot-notation lookup used by t() function

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

custom_components/wled_screen_controller/__init__.py

@@ -18,8 +18,10 @@ from .const import (
     TARGET_TYPE_KEY_COLORS,
     DATA_COORDINATOR,
     DATA_WS_MANAGER,
+    DATA_EVENT_LISTENER,
 )
 from .coordinator import WLEDScreenControllerCoordinator
+from .event_listener import EventStreamListener
 from .ws_manager import KeyColorsWebSocketManager
 
 _LOGGER = logging.getLogger(__name__)
@@ -48,6 +50,9 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
 
     ws_manager = KeyColorsWebSocketManager(hass, server_url, api_key)
 
+    event_listener = EventStreamListener(hass, server_url, api_key, coordinator)
+    await event_listener.start()
+
     # Create device entries for each target
     device_registry = dr.async_get(hass)
     if coordinator.data and "targets" in coordinator.data:
@@ -73,6 +78,7 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
     hass.data[DOMAIN][entry.entry_id] = {
         DATA_COORDINATOR: coordinator,
         DATA_WS_MANAGER: ws_manager,
+        DATA_EVENT_LISTENER: event_listener,
     }
 
     # Track target IDs to detect changes
@@ -114,10 +120,9 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
 
 async def async_unload_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
     """Unload a config entry."""
-    ws_manager: KeyColorsWebSocketManager = hass.data[DOMAIN][entry.entry_id][
-        DATA_WS_MANAGER
-    ]
-    await ws_manager.shutdown()
+    entry_data = hass.data[DOMAIN][entry.entry_id]
+    await entry_data[DATA_WS_MANAGER].shutdown()
+    await entry_data[DATA_EVENT_LISTENER].shutdown()
 
     unload_ok = await hass.config_entries.async_unload_platforms(entry, PLATFORMS)