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/app/not-found.tsx

@@ -0,0 +1,32 @@
+import Link from 'next/link';
+import { Button } from '@/components/ui/button';
+import {
+  Card,
+  CardContent,
+  CardFooter,
+  CardHeader,
+  CardTitle,
+} from '@/components/ui/card';
+
+export default function NotFound() {
+  return (
+    <div className="flex min-h-[50vh] items-center justify-center p-6">
+      <Card className="max-w-md w-full">
+        <CardHeader>
+          <CardTitle>Page not found</CardTitle>
+        </CardHeader>
+        <CardContent>
+          <p className="text-muted-foreground">
+            The page you&apos;re looking for doesn&apos;t exist or has been
+            moved.
+          </p>
+        </CardContent>
+        <CardFooter>
+          <Button asChild>
+            <Link href="/">Go home</Link>
+          </Button>
+        </CardFooter>
+      </Card>
+    </div>
+  );
+}