refactor: migrate to monorepo structure with Docker, PocketBase, and e2e tests

- Reorganize into apps/, packages/, docs/, e2e/, pocketbase/ directories
- Add Dockerfiles for web, worker, and PocketBase services
- Add docker-compose.yml for local orchestration
- Add turbo.json for monorepo task management
- Add Playwright e2e test infrastructure
- Add PocketBase backend with migrations
- Remove Vite/Next.js/ESLint/PostCSS config files
- Update package.json with workspace dependencies
- Add .env.example and .dockerignore

apps/web/components/network-error-banner.tsx

@@ -0,0 +1,48 @@
+'use client';
+
+import { useEffect, useState } from 'react';
+import { AlertCircle, RefreshCw } from 'lucide-react';
+import { Button } from '@/components/ui/button';
+
+export function NetworkErrorBanner() {
+  const [isOffline, setIsOffline] = useState(false);
+
+  useEffect(() => {
+    const handleOffline = () => setIsOffline(true);
+    const handleOnline = () => setIsOffline(false);
+
+    window.addEventListener('offline', handleOffline);
+    window.addEventListener('online', handleOnline);
+
+    setIsOffline(!navigator.onLine);
+
+    return () => {
+      window.removeEventListener('offline', handleOffline);
+      window.removeEventListener('online', handleOnline);
+    };
+  }, []);
+
+  if (!isOffline) return null;
+
+  return (
+    <div
+      className="fixed top-0 left-0 right-0 z-50 flex items-center justify-center gap-3 bg-destructive px-4 py-2 text-destructive-foreground shadow-lg"
+      role="alert"
+      aria-live="assertive"
+    >
+      <AlertCircle className="h-4 w-4" aria-hidden="true" />
+      <span className="text-sm font-medium">
+        You&apos;re offline. Some features may not work.
+      </span>
+      <Button
+        variant="ghost"
+        size="sm"
+        className="h-7 gap-1 px-2 text-xs"
+        onClick={() => window.location.reload()}
+      >
+        <RefreshCw className="h-3 w-3" aria-hidden="true" />
+        Retry
+      </Button>
+    </div>
+  );
+}