refactor: enhance error handling and masking for model not found scenarios

middleware/distributor.go

@@ -107,11 +107,11 @@ func Distribute() func(c *gin.Context) {
 					//	common.SysError(fmt.Sprintf("渠道不存在：%d", channel.Id))
 					//	message = "数据库一致性已被破坏，请联系管理员"
 					//}
-					abortWithOpenAiMessage(c, http.StatusServiceUnavailable, message)
+					abortWithOpenAiMessage(c, http.StatusServiceUnavailable, message, string(types.ErrorCodeModelNotFound))
 					return
 				}
 				if channel == nil {
-					abortWithOpenAiMessage(c, http.StatusServiceUnavailable, fmt.Sprintf("分组 %s 下模型 %s 无可用渠道（distributor）", userGroup, modelRequest.Model))
+					abortWithOpenAiMessage(c, http.StatusServiceUnavailable, fmt.Sprintf("分组 %s 下模型 %s 无可用渠道（distributor）", userGroup, modelRequest.Model), string(types.ErrorCodeModelNotFound))
 					return
 				}
 			}