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/lodash/_Map.js

@@ -0,0 +1,7 @@
+var getNative = require('./_getNative'),
+    root = require('./_root');
+
+/* Built-in method references that are verified to be native. */
+var Map = getNative(root, 'Map');
+
+module.exports = Map;