Implement client-side resilience UI

Create NetworkErrorBanner, SubmissionQueueIndicator, and enhanced retry progress UI components. Integrate them into the application using a ResilienceProvider to manage network status and submission queue states. Update App.tsx to include the ResilienceProvider.

src/hooks/useNetworkStatus.ts

@@ -0,0 +1,28 @@
+import { useState, useEffect } from 'react';
+
+export function useNetworkStatus() {
+  const [isOnline, setIsOnline] = useState(navigator.onLine);
+  const [wasOffline, setWasOffline] = useState(false);
+
+  useEffect(() => {
+    const handleOnline = () => {
+      setIsOnline(true);
+      setWasOffline(false);
+    };
+
+    const handleOffline = () => {
+      setIsOnline(false);
+      setWasOffline(true);
+    };
+
+    window.addEventListener('online', handleOnline);
+    window.addEventListener('offline', handleOffline);
+
+    return () => {
+      window.removeEventListener('online', handleOnline);
+      window.removeEventListener('offline', handleOffline);
+    };
+  }, []);
+
+  return { isOnline, wasOffline };
+}