feat: add keepPreviousData for smooth pagination

apps/frontend/src/hooks/useBrokerOperations.ts

@@ -1,4 +1,4 @@
-import { useQuery } from '@tanstack/react-query';
+import { keepPreviousData, useQuery } from '@tanstack/react-query';
 import { getBrokerOperations, type BrokerOperationQuery } from '../api/broker';
 import type { BrokerOperationsPage } from '../api/responses';
 
@@ -12,6 +12,7 @@ export function useBrokerOperations(
     queryFn: async () => (await getBrokerOperations(accountId!, query)).data,
     staleTime: 300_000,
     retry: 2,
+    placeholderData: keepPreviousData,
     refetchOnWindowFocus: false,
   });
 }