feat: 누락된 데이터 추가

Related to: #136

Author: rudeh1253

src/main/java/com/hf/healthfriend/domain/chat/dto/response/ChatroomListResponseDto.java

@@ -3,6 +3,8 @@
 import com.hf.healthfriend.domain.matching.constant.MatchingStatus;
 import lombok.Builder;
 
+import java.time.LocalDateTime;
+
 @Builder
 public record ChatroomListResponseDto(
         Long chatroomId,
@@ -11,6 +13,7 @@ public record ChatroomListResponseDto(
         String opponentParticipantProfileImageUrl,
         MatchingStatus matchingStatus,
         String lastChatMessage,
+        LocalDateTime chatSentTime,
         Integer unreadMessageCount
 ) {
 }

src/main/java/com/hf/healthfriend/domain/chat/service/ChatService.java

@@ -75,6 +75,7 @@ public List<ChatroomListResponseDto> getChatroomList(Long participantId,
                                 .opponentParticipantProfileImageUrl(this.fileUrlResolver.resolveFileUrl(dto.opponentParticipantProfileImageUrl()))
                                 .matchingStatus(dto.matchingStatus())
                                 .lastChatMessage(dto.chatroom().getLastChatMessage().getMessageAsText())
+                                .chatSentTime(dto.chatroom().getCreationTime()) // lastModified를 반환하는 게 맞을까?
                                 .unreadMessageCount(dto.chatroom().getUnreadMessageCount())
                                 .build()
                 )