Fix camera feed freezing and person detection alerts

- Add WebRTC auto-reconnect with exponential backoff when streams
  disconnect or fail, preventing permanent freezes in grid view
- Replace hard-coded Front Porch person alert with generic system
  that monitors all configured personDetectionEntities
- Map Frigate person_occupancy entities to cameras dynamically
- Show correct camera name and feed in alert overlay
- Bump config version to refresh detection entity defaults

src/stores/settingsStore.ts

@@ -2,7 +2,7 @@ import { create } from 'zustand';
 import { persist } from 'zustand/middleware';
 
 // Increment this when default cameras/config changes to force refresh
-const CONFIG_VERSION = 8;
+const CONFIG_VERSION = 9;
 
 export interface ThermostatConfig {
   entityId: string;