로그인 페이지 및 기능 구현

frontend/lib/features/auth/presentation/login_screen.dart

@@ -540,6 +540,17 @@ class _LoginScreenState extends ConsumerState<LoginScreen>
                                     child: const Text("로그인 링크 전송"),
                                   ),
                                   const SizedBox(height: 16),
+                                  Row(
+                                    mainAxisAlignment: MainAxisAlignment.center,
+                                    children: [
+                                      const Text("계정이 없으신가요?", style: TextStyle(color: Colors.grey, fontSize: 14)),
+                                      TextButton(
+                                        onPressed: () => context.push('/signup'),
+                                        child: const Text("회원가입"),
+                                      ),
+                                    ],
+                                  ),
+                                  const SizedBox(height: 16),
                                   const Text(
                                     "입력하신 정보로 로그인 링크를 전송합니다.",
                                     style: TextStyle(color: Colors.grey, fontSize: 12),