perf(chat): 分页客服会话并拆分统计查询

backend/internal/modules/chat/listing_group.go

@@ -195,7 +195,7 @@ func AddRenterToListingConversation(tx *gorm.DB, listingID uint64, renterID uint
 	if handoffSupportID > 0 {
 		message += "，卖号组客服已接入"
 	}
-	return sendSystemMessage(tx, conv.ID, message)
+	return sendSystemMessageWithAttention(tx, conv.ID, message, "order_paid")
 }
 
 // RemoveRenterFromListingConversation 移出租客，返回是否真的删除了租客成员记录。
@@ -248,13 +248,18 @@ func getListingGroupWelcomeMessage(tx *gorm.DB) string {
 }
 
 func sendSystemMessage(tx *gorm.DB, conversationID uint64, content string) error {
+	return sendSystemMessageWithAttention(tx, conversationID, content, "")
+}
+
+func sendSystemMessageWithAttention(tx *gorm.DB, conversationID uint64, content, attentionType string) error {
 	message := model.ChatMessage{
-		ConversationID: conversationID,
-		SenderType:     "system",
-		SenderRole:     "system",
-		ContentType:    "system",
-		Content:        content,
-		AttachmentURLS: emptyJSONList(),
+		ConversationID:     conversationID,
+		SenderType:         "system",
+		SenderRole:         "system",
+		ContentType:        "system",
+		Content:            content,
+		AttachmentURLS:     emptyJSONList(),
+		AdminAttentionType: attentionType,
 	}
 
 	if err := tx.Create(&message).Error; err != nil {