[fix] 온보딩 완료 후 권한이 적용되지 않는 문제

Author: floreo1242

src/main/java/kr/dgucaps/caps/domain/auth/service/AuthService.java

@@ -72,10 +72,10 @@ public void completeRegistration(Long memberId, CompleteRegistrationRequest requ
 
         memberListRepository.findByStudentIdAndPhoneNumber(request.studentNumber(), request.phoneNumber().replaceAll("-", ""))
                 .ifPresent(memberList -> member.updateRole(Role.MEMBER));
-        memberRepository.save(member);
+        Member savedMember = memberRepository.save(member);
 
         // 업데이트된 권한을 반영한 Authentication 객체 생성
-        Authentication authentication = new UsernamePasswordAuthenticationToken(String.valueOf(memberId), null, Collections.singletonList(member.getRole()));
+        Authentication authentication = new UsernamePasswordAuthenticationToken(String.valueOf(memberId), null, Collections.singletonList(savedMember.getRole()));
         String accessToken = jwtProvider.generateAccessToken(authentication);
         String refreshToken = jwtProvider.generateRefreshToken(authentication);