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/beaker.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 Beaker = createLucideIcon("Beaker", [
+  ["path", { d: "M4.5 3h15", key: "c7n0jr" }],
+  ["path", { d: "M6 3v16a2 2 0 0 0 2 2h8a2 2 0 0 0 2-2V3", key: "m1uhx7" }],
+  ["path", { d: "M6 14h12", key: "4cwo0f" }]
+]);
+
+export { Beaker as default };
+//# sourceMappingURL=beaker.js.map