fix: use Database icon for Local Archives stat card

- Changed from Archive to Database icon
- Better semantic representation of database backups
- Improves UI clarity and consistency

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

frontend/app/admin/page.tsx

@@ -30,8 +30,7 @@ import {
   Database,
   Layers,
   X,
-  ChevronDown,
-  Archive
+  ChevronDown
 } from 'lucide-react';
 import { toast } from 'react-hot-toast';
 import { cn } from '@/lib/utils';
@@ -761,7 +760,7 @@ export default function AdminPage() {
               </div>
             </div>
             <div className="pl-6">
-              <StatCard label="Local Archives" value={dbStats.backup_count} icon={Archive} />
+              <StatCard label="Local Archives" value={dbStats.backup_count} icon={Database} />
             </div>
           </div>
         </section>