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-create-arrow.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 GitPullRequestCreateArrow = createLucideIcon("GitPullRequestCreateArrow", [
+  ["circle", { cx: "5", cy: "6", r: "3", key: "1qnov2" }],
+  ["path", { d: "M5 9v12", key: "ih889a" }],
+  ["path", { d: "m15 9-3-3 3-3", key: "1lwv8l" }],
+  ["path", { d: "M12 6h5a2 2 0 0 1 2 2v3", key: "1rbwk6" }],
+  ["path", { d: "M19 15v6", key: "10aioa" }],
+  ["path", { d: "M22 18h-6", key: "1d5gi5" }]
+]);
+
+export { GitPullRequestCreateArrow as default };
+//# sourceMappingURL=git-pull-request-create-arrow.js.map