Add entity CRUD events over WebSocket with auto-refresh

Broadcast entity_changed and device_health_changed events via the event
bus so the frontend can auto-refresh cards without polling. Adds
exponential backoff on WS reconnect.

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

server/src/wled_controller/core/automations/automation_engine.py

@@ -393,7 +393,7 @@ class AutomationEngine:
 
     def _fire_event(self, automation_id: str, action: str) -> None:
         try:
-            self._manager._fire_event({
+            self._manager.fire_event({
                 "type": "automation_state_changed",
                 "automation_id": automation_id,
                 "action": action,