[Server] 댓글 수정, 삭제

#제목에 [Client], [Server] 꼭 써주세요!
#Labels 꼭 추가해야하는 라벨!
Type: feature, bug
Estimated time(예상소요시간) : 1h
Urgency(버그 중요도) : High, Middle, Low (버그있을때만 라벨넣어주시면 됩니다!)

###TODO 최대한 세세하게 써주세요!
- [ ] UPDATE or POST 요청시 DB 댓글 내용만 수정
- [ ] DELETE 요청시 댓글 삭제

###Estimated time
> 하나를 골라주세요! 라벨만 추가해주시면 됩니다~!~!
- 0.5h
- 1h
- 1.5h
- 2h
- 2.5h
- 3h

Start by locating the server handlers for comment UPDATE or POST requests and the DELETE request, then trace how comment records are stored. Done means an update changes only the database comment content and a delete removes the comment record; verify both request paths with the project’s available checks.

Rédigé par le modèle d'indexation à partir du texte de l'issue.