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/sparkle.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 Sparkle = createLucideIcon("Sparkle", [
+  [
+    "path",
+    {
+      d: "m12 3-1.9 5.8a2 2 0 0 1-1.287 1.288L3 12l5.8 1.9a2 2 0 0 1 1.288 1.287L12 21l1.9-5.8a2 2 0 0 1 1.287-1.288L21 12l-5.8-1.9a2 2 0 0 1-1.288-1.287Z",
+      key: "nraa5p"
+    }
+  ]
+]);
+
+export { Sparkle as default };
+//# sourceMappingURL=sparkle.js.map