feat: add user management to admin panel (add, delete, change password)

app/admin/components/Sidebar.tsx

@@ -2,7 +2,7 @@
 
 import Link from 'next/link';
 import { usePathname, useRouter } from 'next/navigation';
-import { LayoutDashboard, Image as ImageIcon, Briefcase, Mail, LogOut, Settings } from 'lucide-react';
+import { LayoutDashboard, Image as ImageIcon, Briefcase, Mail, LogOut, Settings, Users } from 'lucide-react';
 import { logout } from '../actions';
 
 const navItems = [
@@ -12,6 +12,7 @@ const navItems = [
   { name: 'Hizmetler', href: '/admin/services', icon: Briefcase },
   { name: 'İletişim Mesajları', href: '/admin/contact', icon: Mail },
   { name: 'Site Ayarları', href: '/admin/settings', icon: Settings },
+  { name: 'Kullanıcılar', href: '/admin/users', icon: Users },
 ];
 
 export function Sidebar() {