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/lib/utils.ts

@@ -1,6 +1,6 @@
-import { clsx, type ClassValue } from "clsx"
-import { twMerge } from "tailwind-merge"
+import { clsx, type ClassValue } from "clsx";
+import { twMerge } from "tailwind-merge";
 
 export function cn(...inputs: ClassValue[]) {
-  return twMerge(clsx(inputs))
+  return twMerge(clsx(inputs));
 }