refactor(auth): OAuth 유저 등록 로직 리팩토링

- `registerOAuthUser` 메서드 제거 및 `SignUpUseCase`로 대체
- `RegisterUserUseCase`와 `OAuthInfoRegistrar` 종속성 제거
- OAuth 유저 등록과 관련된 책임을 `SignUpUseCase`로 위임

src/main/java/com/somemore/global/auth/oauth/processor/OAuthUserProcessorImpl.java

@@ -4,29 +4,23 @@
 import com.somemore.global.auth.oauth.converter.OAuthResponseConverter;
 import com.somemore.global.auth.oauth.domain.CommonOAuthInfo;
 import com.somemore.global.auth.oauth.domain.CustomOAuth2User;
-import com.somemore.global.auth.oauth.registrar.OAuthInfoRegistrar;
 import com.somemore.global.auth.oauth.service.OAuthInfoQueryService;
-import com.somemore.user.domain.User;
-import com.somemore.user.domain.UserRole;
-import com.somemore.user.usecase.RegisterUserUseCase;
+import com.somemore.global.auth.sign.up.SignUpUseCase;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.stereotype.Service;
-import org.springframework.transaction.annotation.Transactional;
 
 import java.util.UUID;
 
 @Slf4j
 @Service
 @RequiredArgsConstructor
-@Transactional
 public class OAuthUserProcessorImpl implements OAuthUserProcessor {
 
     private final OAuthResponseConverter oauthResponseConverter;
     private final OAuthInfoChecker oauthInfoChecker;
-    private final OAuthInfoRegistrar oauthInfoRegistrar;
-    private final RegisterUserUseCase registerUserUseCase;
     private final OAuthInfoQueryService oAuthInfoQueryService;
+    private final SignUpUseCase signUpUseCase;
 
     @Override
     public UUID fetchUserIdByOAuthUser(CustomOAuth2User oauthUser) {
@@ -36,29 +30,12 @@ public UUID fetchUserIdByOAuthUser(CustomOAuth2User oauthUser) {
 
     private UUID findUserIdByOAuthInfo(CommonOAuthInfo oauthInfo) {
         if (isNewUser(oauthInfo)) {
-            User user = registerOAuthUser(oauthInfo);
-            return user.getId();
+            signUpUseCase.signUpOAuthUser(oauthInfo);
         }
         return oAuthInfoQueryService.getUserIdByCommonOAuthInfo(oauthInfo);
     }
 
-    private User registerOAuthUser(CommonOAuthInfo oauthInfo) {
-        User user = registerUser(oauthInfo);
-        registerOAuthInfo(user, oauthInfo);
-        // TODO 봉사자 등록 이벤트 발행
-
-        return user;
-    }
-
     private boolean isNewUser(CommonOAuthInfo oauthInfo) {
         return !oauthInfoChecker.doesUserExist(oauthInfo.provider(), oauthInfo.oauthId());
     }
-
-    private User registerUser(CommonOAuthInfo oauthInfo) {
-        return registerUserUseCase.registerOAuthUser(oauthInfo, UserRole.getOAuthUserDefaultRole());
-    }
-
-    private void registerOAuthInfo(User user, CommonOAuthInfo oauthInfo) {
-        oauthInfoRegistrar.register(user, oauthInfo);
-    }
 }