fix(server): improve message handling and data privacy

- fix unread count calculation logic in message repository
- implement logic to retrieve other participant's last read sequence in conversation handlers
- mask real names in verification record responses for privacy
- improve error reporting in main entry point by using stderr instead of zap logger during initialization

internal/handler/message_handler.go

@@ -244,6 +244,12 @@ func (h *MessageHandler) GetConversationByID(c *gin.Context) {
 
 	// 获取对方用户的已读位置
 	otherLastReadSeq := int64(0)
+	for _, p := range allParticipants {
+		if p.UserID != userID {
+			otherLastReadSeq = p.LastReadSeq
+			break
+		}
+	}
 	response.Success(c, dto.ConvertConversationToDetailResponse(conv, participants, unreadCount, nil, myLastReadSeq, otherLastReadSeq, isPinned, notificationMuted))
 }
 
@@ -768,6 +774,12 @@ func (h *MessageHandler) HandleGetConversation(c *gin.Context) {
 
 	// 获取对方用户的已读位置
 	otherLastReadSeq := int64(0)
+	for _, p := range allParticipants {
+		if p.UserID != userID {
+			otherLastReadSeq = p.LastReadSeq
+			break
+		}
+	}
 	response.Success(c, dto.ConvertConversationToDetailResponse(conv, participants, unreadCount, nil, myLastReadSeq, otherLastReadSeq, isPinned, notificationMuted))
 }