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/d3-array/src/groupSort.js

@@ -0,0 +1,10 @@
+import ascending from "./ascending.js";
+import group, {rollup} from "./group.js";
+import sort from "./sort.js";
+
+export default function groupSort(values, reduce, key) {
+  return (reduce.length !== 2
+    ? sort(rollup(values, reduce, key), (([ak, av], [bk, bv]) => ascending(av, bv) || ascending(ak, bk)))
+    : sort(group(values, key), (([ak, av], [bk, bv]) => reduce(av, bv) || ascending(ak, bk))))
+    .map(([key]) => key);
+}