refactor(jpush): move vendor field handling into ThirdPartyChannel struct

Move the vendor switch logic into the ThirdPartyChannel struct as Set/IsEmpty/Normalize
methods to improve encapsulation and eliminate code duplication in the vendor params
builder. Also simplify messageToParams to reuse buildMessagePayload results and remove
unused notification_type extras from push notifications.

internal/service/push_service.go

@@ -617,17 +617,18 @@ func (s *pushServiceImpl) buildPayload(params vendor.MessageParams) *vendor.Push
 
 // messageToParams 从 model.Message 提取厂商无关的统一参数
 // 用于 PushToUser / worker / retry 等通用路径
+// 复用 buildMessagePayload 的计算结果，避免重复解析 message
 func (s *pushServiceImpl) messageToParams(message *model.Message) vendor.MessageParams {
-	_ = message.Decrypt()
 	payload := buildMessagePayload(message)
-	scene := s.resolveChannelScene(message)
-
+	// senderName 复用 payload.Extras 中已提取的 actor_name，无需再次访问 ExtraData
 	senderName := ""
-	if message.ExtraData != nil {
-		senderName = message.ExtraData.ActorName
+	if name, ok := payload.Extras["actor_name"]; ok {
+		if n, ok := name.(string); ok {
+			senderName = n
+		}
 	}
 	return vendor.MessageParams{
-		Scene:       scene,
+		Scene:       s.resolveChannelScene(message),
 		Title:       payload.Title,
 		Body:        payload.Content,
 		SenderName:  senderName,
@@ -787,7 +788,6 @@ func (s *pushServiceImpl) PushChatMessage(ctx context.Context, userID string, co
 		content = "[非文本消息]"
 	}
 	extras := map[string]any{
-		"notification_type": "chat_message",
 		"message_id":        message.ID,
 		"conversation_id":   message.ConversationID,
 		"conversation_type": string(convType),
@@ -900,8 +900,7 @@ func (s *pushServiceImpl) PushSystemNotification(ctx context.Context, userID str
 					title = string(notification.Type)
 				}
 				extras := map[string]any{
-					"notification_id":   fmt.Sprintf("%d", notification.ID),
-					"notification_type": string(notification.Type),
+					"notification_id": fmt.Sprintf("%d", notification.ID),
 				}
 				if notification.ExtraData != nil {
 					extras["actor_id"] = notification.ExtraData.ActorIDStr