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/superPropSet.js

@@ -0,0 +1,6 @@
+import set from "./set.js";
+import getPrototypeOf from "./getPrototypeOf.js";
+function _superPropSet(t, e, o, r, p, f) {
+  return set(getPrototypeOf(f ? t.prototype : t), e, o, r, p);
+}
+export { _superPropSet as default };