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/react-transition-group/cjs/index.js

@@ -0,0 +1,30 @@
+"use strict";
+
+exports.__esModule = true;
+exports.config = exports.Transition = exports.TransitionGroup = exports.SwitchTransition = exports.ReplaceTransition = exports.CSSTransition = void 0;
+
+var _CSSTransition = _interopRequireDefault(require("./CSSTransition"));
+
+exports.CSSTransition = _CSSTransition.default;
+
+var _ReplaceTransition = _interopRequireDefault(require("./ReplaceTransition"));
+
+exports.ReplaceTransition = _ReplaceTransition.default;
+
+var _SwitchTransition = _interopRequireDefault(require("./SwitchTransition"));
+
+exports.SwitchTransition = _SwitchTransition.default;
+
+var _TransitionGroup = _interopRequireDefault(require("./TransitionGroup"));
+
+exports.TransitionGroup = _TransitionGroup.default;
+
+var _Transition = _interopRequireDefault(require("./Transition"));
+
+exports.Transition = _Transition.default;
+
+var _config = _interopRequireDefault(require("./config"));
+
+exports.config = _config.default;
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }