Merge branch 's-choi' of https://gitea.it-college.co.jp/2026_09_5H_Spring_KIZAKI/Monegement into k-kobayashi

src/main/java/com/example/demo/app/domain/service/impl/LoginServiceImpl.java

@@ -25,6 +25,8 @@ public class LoginServiceImpl implements LoginService {
 
 		if (userEntity == null) {
 			return null;
+		} else if (userEntity.getDeleteFlag() == 1) {
+			return null;
 		}
 
 		boolean isValidPassword = false;