feat: add admin links management and updaterup page

- Implemented AdminLinksPage for managing link entries with admin role check.
- Created API routes for fetching, updating, and deleting link entries.
- Added ProductTabs component for navigation between Backerup and Updaterup.
- Developed UpdaterupPage with detailed features, setup instructions, and statistics.
- Introduced links database functionality for runtime-editable link overrides.

frontend/app/admin/page.tsx

@@ -16,27 +16,5 @@ export default async function AdminPage() {
 
   const users = await listUsers()
 
-  return (
-    <div className="mx-auto max-w-2xl px-4 py-12">
-      {/* Header */}
-      <div className="mb-10">
-        <div className="flex items-center gap-3 mb-2">
-          <div
-            className="w-9 h-9 rounded-xl flex items-center justify-center"
-            style={{ background: 'linear-gradient(135deg, #a78bfa, #7c3aed)' }}
-          >
-            <svg viewBox="0 0 20 20" fill="currentColor" className="w-4 h-4 text-white" aria-hidden="true">
-              <path d="M10 9a3 3 0 100-6 3 3 0 000 6zM6 8a2 2 0 11-4 0 2 2 0 014 0zM1.49 15.326a.78.78 0 01-.358-.442 3 3 0 014.308-3.516 6.484 6.484 0 00-1.905 3.959c-.023.222-.014.442.025.654a4.97 4.97 0 01-2.07-.655zM16.44 15.98a4.97 4.97 0 002.07-.654.78.78 0 00.357-.442 3 3 0 00-4.308-3.517 6.484 6.484 0 011.907 3.96 2.32 2.32 0 01-.026.654zM18 8a2 2 0 11-4 0 2 2 0 014 0zM5.304 16.19a.844.844 0 01-.277-.71 5 5 0 019.947 0 .843.843 0 01-.277.71A6.975 6.975 0 0110 18a6.974 6.974 0 01-4.696-1.81z" />
-            </svg>
-          </div>
-          <div>
-            <h1 className="text-xl font-bold text-white">User Management</h1>
-            <p className="text-sm text-slate-400">Manage accounts and permissions</p>
-          </div>
-        </div>
-      </div>
-
-      <UsersClient initialUsers={users} currentUserId={session.userId} />
-    </div>
-  )
+  return <UsersClient initialUsers={users} currentUserId={session.userId} />
 }