refactor(hub): migrate dashboard to shadcn components

Replace manual CSS classes with shadcn Card, CardHeader, CardTitle,
CardContent, and Badge components. Remove inline <style> block —
use Tailwind utility classes via shadcn theme tokens. Add Biome
formatting across all components.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/components/ui/skeleton.tsx

@@ -1,4 +1,4 @@
-import { cn } from "@/lib/utils"
+import { cn } from "@/lib/utils";
 
 function Skeleton({ className, ...props }: React.ComponentProps<"div">) {
   return (
@@ -7,7 +7,7 @@ function Skeleton({ className, ...props }: React.ComponentProps<"div">) {
       className={cn("animate-pulse rounded-md bg-muted", className)}
       {...props}
     />
-  )
+  );
 }
 
-export { Skeleton }
+export { Skeleton };