feat: Home Assistant integration — WebSocket connection, automation conditions, UI

Add full Home Assistant integration via WebSocket API:
- HARuntime: persistent WebSocket client with auth, auto-reconnect, entity state cache
- HAManager: ref-counted runtime pool (like WeatherManager)
- HomeAssistantCondition: new automation trigger type matching entity states
- REST API: CRUD for HA sources + /test, /entities, /status endpoints
- /api/v1/system/integrations-status: combined MQTT + HA dashboard indicators
- Frontend: HA Sources tab in Streams, condition type in automation editor
- Modal editor with host, token, SSL, entity filters
- websockets>=13.0 dependency added

server/src/wled_controller/api/__init__.py

@@ -27,6 +27,7 @@ from .routes.gradients import router as gradients_router
 from .routes.weather_sources import router as weather_sources_router
 from .routes.update import router as update_router
 from .routes.assets import router as assets_router
+from .routes.home_assistant import router as home_assistant_router
 
 router = APIRouter()
 router.include_router(system_router)
@@ -54,5 +55,6 @@ router.include_router(gradients_router)
 router.include_router(weather_sources_router)
 router.include_router(update_router)
 router.include_router(assets_router)
+router.include_router(home_assistant_router)
 
 __all__ = ["router"]