fix(chat): 回复后再移出待处理

backend/internal/modules/chat/participant.go

@@ -33,6 +33,7 @@ type conversationRow struct {
 	LastSenderID        uint64
 	LastSenderRole      string
 	UnreadCount         int64
+	NeedsReply          int64
 	CreatedAt           time.Time
 	UpdatedAt           time.Time
 }
@@ -333,6 +334,7 @@ func (row conversationRow) toDTO(participants []ParticipantDTO) ConversationDTO
 		LastSenderID:        row.LastSenderID,
 		LastSenderRole:      row.LastSenderRole,
 		UnreadCount:         row.UnreadCount,
+		NeedsReply:          row.NeedsReply > 0,
 		CreatedAt:           row.CreatedAt,
 		UpdatedAt:           row.UpdatedAt,
 	}