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/maybeArrayLike.js

@@ -0,0 +1,9 @@
+var arrayLikeToArray = require("./arrayLikeToArray.js");
+function _maybeArrayLike(r, a, e) {
+  if (a && !Array.isArray(a) && "number" == typeof a.length) {
+    var y = a.length;
+    return arrayLikeToArray(a, void 0 !== e && e < y ? e : y);
+  }
+  return r(a, e);
+}
+module.exports = _maybeArrayLike, module.exports.__esModule = true, module.exports["default"] = module.exports;