feat: 사용 중인 전화번호 검증 로직 추가(#78)

be/src/main/java/yeonba/be/login/service/LoginService.java

@@ -9,9 +9,11 @@
 import yeonba.be.login.dto.request.UserLoginRequest;
 import yeonba.be.login.dto.request.UserRefreshJwtRequest;
 import yeonba.be.login.dto.request.UserValidateUsedNicknameRequest;
+import yeonba.be.login.dto.request.UserValidateUsedPhoneNumberRequest;
 import yeonba.be.login.dto.response.UserLoginResponse;
 import yeonba.be.login.dto.response.UserRefrehJwtResponse;
 import yeonba.be.login.dto.response.UserValidateUsedNicknameResponse;
+import yeonba.be.login.dto.response.UserValidateUsedPhoneNumberResponse;
 import yeonba.be.user.entity.User;
 import yeonba.be.user.enums.LoginType;
 import yeonba.be.user.repository.user.UserQuery;
@@ -74,4 +76,13 @@ public UserValidateUsedNicknameResponse validateUsedNickname(
 
         return new UserValidateUsedNicknameResponse(usedNickname);
     }
+
+    @Transactional(readOnly = true)
+    public UserValidateUsedPhoneNumberResponse validateUsedPhoneNumber(
+        UserValidateUsedPhoneNumberRequest request) {
+
+        boolean usedPhoneNumber = userQuery.validateUsedPhoneNumber(request.getPhoneNumber());
+
+        return new UserValidateUsedPhoneNumberResponse(usedPhoneNumber);
+    }
 }