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/lucide-react/dist/esm/icons/gitlab.js

@@ -0,0 +1,21 @@
+/**
+ * @license lucide-react v0.303.0 - ISC
+ *
+ * This source code is licensed under the ISC license.
+ * See the LICENSE file in the root directory of this source tree.
+ */
+
+import createLucideIcon from '../createLucideIcon.js';
+
+const Gitlab = createLucideIcon("Gitlab", [
+  [
+    "path",
+    {
+      d: "m22 13.29-3.33-10a.42.42 0 0 0-.14-.18.38.38 0 0 0-.22-.11.39.39 0 0 0-.23.07.42.42 0 0 0-.14.18l-2.26 6.67H8.32L6.1 3.26a.42.42 0 0 0-.1-.18.38.38 0 0 0-.26-.08.39.39 0 0 0-.23.07.42.42 0 0 0-.14.18L2 13.29a.74.74 0 0 0 .27.83L12 21l9.69-6.88a.71.71 0 0 0 .31-.83Z",
+      key: "148pdi"
+    }
+  ]
+]);
+
+export { Gitlab as default };
+//# sourceMappingURL=gitlab.js.map