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/@babel/runtime/helpers/esm/temporalRef.js

@@ -0,0 +1,6 @@
+import temporalUndefined from "./temporalUndefined.js";
+import tdz from "./tdz.js";
+function _temporalRef(r, e) {
+  return r === temporalUndefined ? tdz(e) : r;
+}
+export { _temporalRef as default };