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/button.tsx

@@ -1,7 +1,7 @@
-import { Button as ButtonPrimitive } from "@base-ui/react/button"
-import { cva, type VariantProps } from "class-variance-authority"
+import { Button as ButtonPrimitive } from "@base-ui/react/button";
+import { cva, type VariantProps } from "class-variance-authority";
 
-import { cn } from "@/lib/utils"
+import { cn } from "@/lib/utils";
 
 const buttonVariants = cva(
   "group/button inline-flex shrink-0 items-center justify-center rounded-lg border border-transparent bg-clip-padding text-sm font-medium whitespace-nowrap transition-all outline-none select-none focus-visible:border-ring focus-visible:ring-3 focus-visible:ring-ring/50 active:not-aria-[haspopup]:translate-y-px disabled:pointer-events-none disabled:opacity-50 aria-invalid:border-destructive aria-invalid:ring-3 aria-invalid:ring-destructive/20 dark:aria-invalid:border-destructive/50 dark:aria-invLine truncated
@@ -37,8 +37,8 @@ const buttonVariants = cva(
       variant: "default",
       size: "default",
     },
-  }
-)
+  },
+);
 
 function Button({
   className,
@@ -52,7 +52,7 @@ function Button({
       className={cn(buttonVariants({ variant, size, className }))}
       {...props}
     />
-  )
+  );
 }
 
-export { Button, buttonVariants }
+export { Button, buttonVariants };