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/objectWithoutPropertiesLoose.js

@@ -0,0 +1,10 @@
+function _objectWithoutPropertiesLoose(r, e) {
+  if (null == r) return {};
+  var t = {};
+  for (var n in r) if ({}.hasOwnProperty.call(r, n)) {
+    if (-1 !== e.indexOf(n)) continue;
+    t[n] = r[n];
+  }
+  return t;
+}
+module.exports = _objectWithoutPropertiesLoose, module.exports.__esModule = true, module.exports["default"] = module.exports;