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/postcss-selector-parser/dist/selectors/universal.js

@@ -0,0 +1,22 @@
+"use strict";
+
+exports.__esModule = true;
+exports["default"] = void 0;
+var _namespace = _interopRequireDefault(require("./namespace"));
+var _types = require("./types");
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { "default": obj }; }
+function _inheritsLoose(subClass, superClass) { subClass.prototype = Object.create(superClass.prototype); subClass.prototype.constructor = subClass; _setPrototypeOf(subClass, superClass); }
+function _setPrototypeOf(o, p) { _setPrototypeOf = Object.setPrototypeOf ? Object.setPrototypeOf.bind() : function _setPrototypeOf(o, p) { o.__proto__ = p; return o; }; return _setPrototypeOf(o, p); }
+var Universal = /*#__PURE__*/function (_Namespace) {
+  _inheritsLoose(Universal, _Namespace);
+  function Universal(opts) {
+    var _this;
+    _this = _Namespace.call(this, opts) || this;
+    _this.type = _types.UNIVERSAL;
+    _this.value = '*';
+    return _this;
+  }
+  return Universal;
+}(_namespace["default"]);
+exports["default"] = Universal;
+module.exports = exports.default;