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/p-limit/async-hooks-stub.js

@@ -0,0 +1,15 @@
+export const AsyncResource = {
+	bind(fn, _type, thisArg) {
+		return fn.bind(thisArg);
+	},
+};
+
+export class AsyncLocalStorage {
+	getStore() {
+		return undefined;
+	}
+
+	run(_store, callback) {
+		return callback();
+	}
+}