Import Tripoli Cloud frontend prototype

React/TypeScript/Vite/Tailwind prototype from the design session (login,
dashboard, photos, backups, settings views with mocked API layer).
Infra work (Rust services, Ansible, OpenTofu) follows in subsequent commits.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

app/src/hooks/useBackups.ts

@@ -0,0 +1,11 @@
+import { useEffect, useState } from 'react';
+import { getBackups } from '../api/backups';
+import type { BackupDevice } from '../types';
+
+export function useBackups() {
+  const [backups, setBackups] = useState<BackupDevice[]>([]);
+  useEffect(() => {
+    void getBackups().then(setBackups);
+  }, []);
+  return backups;
+}