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/dns.js

@@ -0,0 +1,16 @@
+
+require('thenify-all').withCallback(
+  require('dns'),
+  exports, [
+    'lookup',
+    'resolve',
+    'resolve4',
+    'resolve6',
+    'resolveCname',
+    'resolveMx',
+    'resolveNs',
+    'resolveSrv',
+    'resolveTxt',
+    'reverse'
+  ]
+)