fix: default cockpit view to grid instead of cards

frontend/src/pages/Dashboard.tsx

@@ -623,7 +623,7 @@ export default function Dashboard() {
 
   const [categoryFilter, setCategoryFilter] = useState('all')
   const [topN, setTopN] = useState(10)
-  const [viewMode, setViewMode] = useState<'cards' | 'grid'>('cards')
+  const [viewMode, setViewMode] = useState<'cards' | 'grid'>('grid')
   const [toast, setToast] = useState<{ title: string; sub: string } | null>(null)
 
   useEffect(() => {