fix(playground): resolve auto group model listing (#6163)

* fix(playground): resolve auto group model listing

- merge and deduplicate available models in configured auto group order.
- reuse special usable group rules and add model filtering regression coverage.

* refactor: extract GetGroupsEnabledModels to dedupe group model expansion

service/group.go

@@ -3,6 +3,7 @@ package service
 import (
 	"strings"
 
+	"github.com/QuantumNous/new-api/model"
 	"github.com/QuantumNous/new-api/setting"
 	"github.com/QuantumNous/new-api/setting/ratio_setting"
 )
@@ -53,6 +54,21 @@ func GetUserAutoGroup(userGroup string) []string {
 	return autoGroups
 }
 
+// GetGroupsEnabledModels 按 groups 顺序获取各分组启用的模型并去重
+func GetGroupsEnabledModels(groups []string) []string {
+	seen := make(map[string]struct{})
+	models := make([]string, 0)
+	for _, group := range groups {
+		for _, modelName := range model.GetGroupEnabledModels(group) {
+			if _, ok := seen[modelName]; !ok {
+				seen[modelName] = struct{}{}
+				models = append(models, modelName)
+			}
+		}
+	}
+	return models
+}
+
 // GetUserGroupRatio 获取用户使用某个分组的倍率
 // userGroup 用户分组
 // group 需要获取倍率的分组