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/templates/index.html

@@ -213,6 +213,7 @@
     {% include 'modals/test-value-source.html' %}
     {% include 'modals/sync-clock-editor.html' %}
     {% include 'modals/weather-source-editor.html' %}
+    {% include 'modals/ha-source-editor.html' %}
     {% include 'modals/asset-upload.html' %}
     {% include 'modals/asset-editor.html' %}
     {% include 'modals/settings.html' %}