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/json5/lib/index.js

@@ -0,0 +1,9 @@
+const parse = require('./parse')
+const stringify = require('./stringify')
+
+const JSON5 = {
+    parse,
+    stringify,
+}
+
+module.exports = JSON5