Merge branch 'develop' of https://github.com/prgrms-web-devcourse-final-project/WEB6_8_Bid_BE into feat#165

Author: Jiwoo-Seo

src/main/java/com/backend/domain/notification/controller/ApiV1NotificationController.java

@@ -90,7 +90,9 @@ public RsData<Integer> getUnreadCount(
     // ======================================= helper methods ======================================= //
     private Long getCurrentMemberId(User user) {
         if (user != null) {
-            return Long.parseLong(user.getUsername());
+            Member member = memberRepository.findByEmail(user.getUsername())
+                    .orElseThrow(() -> new RuntimeException("멤버를 찾을 수 없습니다."));
+            return member.getId();
         } else {
             // 테스트용: 인증이 없으면 첫 번째 사용자 사용
             Member member = memberRepository.findAll().stream().findFirst()