add WebSocket support for real-time delivery updates with JWT authentication and automatic reconnection

frontend/src/App.tsx

@@ -7,6 +7,7 @@ import { Button } from './components/ui/Button';
 import { UpdatePrompt } from './components/ui/UpdatePrompt';
 import { useDeliveryStore } from './stores/deliveryStore';
 import { useAuthStore } from './stores/authStore';
+import { useWebSocket } from './hooks/useWebSocket';
 
 // Lazy load pages for code splitting
 const Dashboard = lazy(() => import('./pages/Dashboard'));
@@ -30,6 +31,8 @@ function App() {
   const addDelivery = useDeliveryStore(state => state.addDelivery);
   const fetchDeliveryCounts = useDeliveryStore(state => state.fetchDeliveryCounts);
 
+  useWebSocket();
+
   // Restore auth on mount
   useEffect(() => {
     restoreAuth();