fix: allow /login route to bypass AuthGuard so login page renders instead of blank

admin/src/components/auth-guard.tsx

@@ -1,17 +1,21 @@
 'use client';
 
 import { useAuth } from '@/lib/auth';
-import { useRouter } from 'next/navigation';
+import { usePathname, useRouter } from 'next/navigation';
 import { useEffect, type ReactNode } from 'react';
 
 export default function AuthGuard({ children }: { children: ReactNode }) {
   const { user, isLoading } = useAuth();
   const router = useRouter();
+  const pathname = usePathname();
+
+  const isLoginPage = pathname === '/login';
 
   useEffect(() => {
-    if (!isLoading && !user) router.replace('/login');
+    if (!isLoginPage && !isLoading && !user) router.replace('/login');
-  }, [user, isLoading, router]);
+  }, [user, isLoading, router, isLoginPage]);
 
+  if (isLoginPage) return <>{children}</>;
   if (isLoading) return <div className="flex h-screen items-center justify-center text-muted-foreground">Cargando...</div>;
   if (!user) return null;