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/chef-hat.js

@@ -0,0 +1,22 @@
+/**
+ * @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 ChefHat = createLucideIcon("ChefHat", [
+  [
+    "path",
+    {
+      d: "M6 13.87A4 4 0 0 1 7.41 6a5.11 5.11 0 0 1 1.05-1.54 5 5 0 0 1 7.08 0A5.11 5.11 0 0 1 16.59 6 4 4 0 0 1 18 13.87V21H6Z",
+      key: "z3ra2g"
+    }
+  ],
+  ["line", { x1: "6", x2: "18", y1: "17", y2: "17", key: "12q60k" }]
+]);
+
+export { ChefHat as default };
+//# sourceMappingURL=chef-hat.js.map