fix: remove per-card Refresh button in InstanceCard, consolidate to page-level refresh

- Remove onRefresh prop from InstanceCard component
- Remove handleRefresh callback from InstancesManagementPage
- Remove onRefresh passing from both filtered and unfiltered instance lists
- Keep global page refresh button in PageHeader

frontend/src/features/artifact/instances/components/InstanceCard.tsx

@@ -27,7 +27,6 @@ interface InstanceCardProps {
   instance: InstanceResponse;
   onModify: (instance: InstanceResponse) => void;
   onTerminate: (instance: InstanceResponse) => void;
-  onRefresh: (instance: InstanceResponse) => void;
   onViewEntries: (instance: InstanceResponse) => void;
   onViewDiagnostics: (instance: InstanceResponse) => void;
 }
@@ -135,7 +134,6 @@ export const InstanceCard: React.FC<InstanceCardProps> = ({
   instance,
   onModify,
   onTerminate,
-  onRefresh,
   onViewEntries,
   onViewDiagnostics,
 }) => {