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/timer.js

@@ -0,0 +1,17 @@
+/**
+ * @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 Timer = createLucideIcon("Timer", [
+  ["line", { x1: "10", x2: "14", y1: "2", y2: "2", key: "14vaq8" }],
+  ["line", { x1: "12", x2: "15", y1: "14", y2: "11", key: "17fdiu" }],
+  ["circle", { cx: "12", cy: "14", r: "8", key: "1e1u0o" }]
+]);
+
+export { Timer as default };
+//# sourceMappingURL=timer.js.map