feat: add permission-gated navigation and admin access

src/app/(modules)/users/page.tsx

@@ -6,6 +6,8 @@ import { Plus, Users } from 'lucide-react';
 import { PageHeader } from '@/components/page-header';
 import { PoweredBy } from '@/components/powered-by';
 import { Button } from '@/components/ui/button';
+import { PERMISSIONS } from '@/constants/permissions';
+import { PermissionGuard } from '@/guards';
 import type { AdministrationUser } from '@/types';
 
 import { useUserColumns } from './components/UserColumns';
@@ -103,10 +105,12 @@ export default function UsersPage() {
           description="Manage users and role assignment"
           icon={Users}
           actions={
-            <Button onClick={openCreate}>
-              <Plus className="mr-2 size-4" />
-              Add User
-            </Button>
+            <PermissionGuard permissions={PERMISSIONS.USER.CREATE}>
+              <Button onClick={openCreate}>
+                <Plus className="mr-2 size-4" />
+                Add User
+              </Button>
+            </PermissionGuard>
           }
         />