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/object-inspect/example/circular.js

@@ -0,0 +1,6 @@
+'use strict';
+
+var inspect = require('../');
+var obj = { a: 1, b: [3, 4] };
+obj.c = obj;
+console.log(inspect(obj));