refactor: login by email (loginId kept as internal identifier)

src/app/(auth)/login/page.tsx

@@ -9,7 +9,7 @@ import type { LoginRequest } from '@/types';
 export default function LoginPage() {
   const router = useRouter();
   const login = useAuthStore((s) => s.login);
-  const [loginId, setLoginId] = useState('');
+  const [email, setEmail] = useState('');
   const [password, setPassword] = useState('');
   const [showPw, setShowPw] = useState(false);
   const [loading, setLoading] = useState(false);
@@ -17,14 +17,14 @@ export default function LoginPage() {
 
   const handleSubmit = async (e: React.FormEvent) => {
     e.preventDefault();
-    if (!loginId.trim() || !password.trim()) {
-      setError('아이디와 비밀번호를 입력해주세요.');
+    if (!email.trim() || !password.trim()) {
+      setError('이메일과 비밀번호를 입력해주세요.');
       return;
     }
     setLoading(true);
     setError('');
     try {
-      await login({ loginId, password } as LoginRequest);
+      await login({ email, password } as LoginRequest);
       router.push('/');
     } catch (err: unknown) {
       const msg = (err as { message?: string })?.message || '로그인에 실패했습니다.';
@@ -53,14 +53,14 @@ export default function LoginPage() {
           )}
 
           <div>
-            <label className="block text-sm font-medium text-text-main mb-1.5">아이디</label>
+            <label className="block text-sm font-medium text-text-main mb-1.5">이메일</label>
             <input
-              type="text"
-              value={loginId}
-              onChange={(e) => setLoginId(e.target.value)}
-              placeholder="아이디를 입력하세요"
+              type="email"
+              value={email}
+              onChange={(e) => setEmail(e.target.value)}
+              placeholder="이메일을 입력하세요"
               className="w-full px-4 py-2.5 rounded-xl border border-border bg-white text-text-main text-sm focus:outline-none focus:ring-2 focus:ring-primary focus:border-transparent transition-all"
-              autoComplete="username"
+              autoComplete="email"
             />
           </div>