refactor: align frontend ownership boundaries

Close audit gaps across API drift, query policy, UI, and tests.

src/test/query.tsx

@@ -0,0 +1,23 @@
+import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
+import type { FC, PropsWithChildren } from "react";
+
+function createTestQueryClient(): QueryClient {
+	return new QueryClient({
+		defaultOptions: {
+			queries: { retry: false },
+			mutations: { retry: false },
+		},
+	});
+}
+
+function createQueryWrapper(queryClient = createTestQueryClient()) {
+	const QueryWrapper: FC<PropsWithChildren> = (props) => (
+		<QueryClientProvider client={queryClient}>
+			{props.children}
+		</QueryClientProvider>
+	);
+
+	return { queryClient, wrapper: QueryWrapper };
+}
+
+export { createQueryWrapper, createTestQueryClient };