feat(frontend): add API client, layout, and routing

- Create Axios-based API client with sources, jobs, and dashboard endpoints
- Add responsive Layout component with navigation sidebar
- Set up React Router with Dashboard, Backups, and Settings routes
- Configure TanStack Query provider with default options
- Use lucide-react for navigation icons

frontend/node_modules/mz/index.js

@@ -0,0 +1,8 @@
+module.exports = {
+  fs: require('./fs'),
+  dns: require('./dns'),
+  zlib: require('./zlib'),
+  crypto: require('./crypto'),
+  readline: require('./readline'),
+  child_process: require('./child_process')
+}