fix: optimistically remove dismissed app from sidebar cache

Sets query cache immediately on dismiss success so the sidebar updates
without waiting for the catalog refetch to complete.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ui/src/api/queries/catalog.ts

@@ -76,7 +76,11 @@ export function useDismissApp() {
       if (res.status === 409) throw new Error('Cannot dismiss — live agents are still connected');
       if (!res.ok) throw new Error(`Failed to dismiss: ${res.status}`);
     },
-    onSuccess: () => {
+    onSuccess: (_data, applicationId) => {
+      // Optimistically remove from cache before refetch
+      qc.setQueriesData<CatalogApp[]>({ queryKey: ['catalog'] }, (old) =>
+        old ? old.filter((a) => a.slug !== applicationId) : old
+      );
       qc.invalidateQueries({ queryKey: ['catalog'] });
     },
   });