improvement: 로그아웃 응답 표준화 및 단일 API 연동 완료 (#253)

- LogoutResponseDto 신규 (logged_out, redirect_to 힌트)
- LogoutAsync 반환 타입 Task → Task<LogoutResponseDto>
- AuthController Swagger 문서에 설정 화면 단일 API 사용 명시

Closes #253

SPMS.API/Controllers/AuthController.cs

@@ -82,8 +82,9 @@ public class AuthController : ControllerBase
     [Authorize]
     [SwaggerOperation(
         Summary = "로그아웃",
-        Description = "현재 로그인된 관리자의 토큰을 무효화합니다. Refresh Token은 DB에서 삭제되고, Access Token은 Redis 블랙리스트에 등록되어 즉시 사용 불가합니다.")]
-    [SwaggerResponse(200, "로그아웃 성공")]
+        Description = "현재 로그인된 관리자의 토큰을 무효화합니다. Refresh Token은 DB에서 삭제되고, Access Token은 Redis 블랙리스트에 등록되어 즉시 사용 불가합니다. " +
+                      "설정/마이페이지/프로필 등 모든 화면에서 이 단일 API를 사용합니다. 응답의 redirect_to로 이동합니다.")]
+    [SwaggerResponse(200, "로그아웃 성공", typeof(ApiResponse<LogoutResponseDto>))]
     [SwaggerResponse(401, "인증되지 않은 요청")]
     public async Task<IActionResult> LogoutAsync()
     {
@@ -94,8 +95,8 @@ public class AuthController : ControllerBase
         var accessToken = HttpContext.Request.Headers["Authorization"]
             .ToString().Replace("Bearer ", "");
 
-        await _authService.LogoutAsync(adminId, accessToken);
-        return Ok(ApiResponse.Success());
+        var result = await _authService.LogoutAsync(adminId, accessToken);
+        return Ok(ApiResponse<LogoutResponseDto>.Success(result));
     }
 
     [HttpPost("email/verify")]

SPMS.Application/DTOs/Auth/LogoutResponseDto.cs

@@ -0,0 +1,12 @@
+using System.Text.Json.Serialization;
+
+namespace SPMS.Application.DTOs.Auth;
+
+public class LogoutResponseDto
+{
+    [JsonPropertyName("logged_out")]
+    public bool LoggedOut { get; set; }
+
+    [JsonPropertyName("redirect_to")]
+    public string RedirectTo { get; set; } = "/login";
+}

SPMS.Application/Interfaces/IAuthService.cs

@@ -8,7 +8,7 @@ public interface IAuthService
     Task<SignupResponseDto> SignupAsync(SignupRequestDto request);
     Task<LoginResponseDto> LoginAsync(LoginRequestDto request);
     Task<TokenRefreshResponseDto> RefreshTokenAsync(TokenRefreshRequestDto request);
-    Task LogoutAsync(long adminId, string accessToken);
+    Task<LogoutResponseDto> LogoutAsync(long adminId, string accessToken);
     Task<ChangePasswordResponseDto> ChangePasswordAsync(long adminId, ChangePasswordRequestDto request);
     Task<EmailCheckResponseDto> CheckEmailAsync(EmailCheckRequestDto request);
     Task<EmailVerifyResponseDto> VerifyEmailAsync(EmailVerifyRequestDto request);

SPMS.Application/Services/AuthService.cs

@@ -287,7 +287,7 @@ public class AuthService : IAuthService
         };
     }
 
-    public async Task LogoutAsync(long adminId, string accessToken)
+    public async Task<LogoutResponseDto> LogoutAsync(long adminId, string accessToken)
     {
         // 1. 관리자 조회
         var admin = await _adminRepository.GetByIdAsync(adminId);
@@ -313,6 +313,12 @@ public class AuthService : IAuthService
             if (remaining > TimeSpan.Zero)
                 await _tokenStore.StoreAsync($"blacklist:{jti}", "revoked", remaining);
         }
+
+        return new LogoutResponseDto
+        {
+            LoggedOut = true,
+            RedirectTo = "/login"
+        };
     }
 
     public async Task<ChangePasswordResponseDto> ChangePasswordAsync(long adminId, ChangePasswordRequestDto request)