feat: board-first orchestration with Gateway Bridge, live-update, and flow-board

- GatewayBridgeController: MCP-artiger Kommando-Adapter für Agent-zu-Backend
- TaskBridgeService + LiveUpdateService: SSE Live-Sync + Bridge-Kommandos
- FlowBoard.vue: Board-first orchestration dashboard panel
- live-sync.ts store + live.ts service: SSE-basierte Live-Updates
- Nullability-Warnung in HealthController.cs gefixt
- nginx.conf: SSE-Proxy + CORS für Bridge-Endpunkte
- .gitignore: pnpm/corepack local caches ausgeschlossen
- docs: architecture-board-first-orchestration.md hinzugefügt
- README: Backend Bridge API dokumentiert

frontend/src/stores/notifications.ts

@@ -84,7 +84,6 @@ export const useNotificationStore = defineStore('notifications', {
     },
 
     startPolling(forUser = 'bao') {
-      // Unread count polling every 30s (for sidebar badge)
       if (!this.countRefreshInterval) {
         this.fetchUnreadCount(forUser)
         this.countRefreshInterval = setInterval(() => {