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/git-pull-request-closed.js

@@ -0,0 +1,20 @@
+/**
+ * @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 GitPullRequestClosed = createLucideIcon("GitPullRequestClosed", [
+  ["circle", { cx: "6", cy: "6", r: "3", key: "1lh9wr" }],
+  ["path", { d: "M6 9v12", key: "1sc30k" }],
+  ["path", { d: "m21 3-6 6", key: "16nqsk" }],
+  ["path", { d: "m21 9-6-6", key: "9j17rh" }],
+  ["path", { d: "M18 11.5V15", key: "65xf6f" }],
+  ["circle", { cx: "18", cy: "18", r: "3", key: "1xkwt0" }]
+]);
+
+export { GitPullRequestClosed as default };
+//# sourceMappingURL=git-pull-request-closed.js.map