feat: 算力引擎 Go 后端核心（new-api）

- 统一 OpenAI 兼容 /v1 中继 + 渠道/额度/令牌/流水
- 各领域包：relay 模型网关、model 数据层、controller 管理 API

setting/auto_group_test.go

@@ -0,0 +1,29 @@
+package setting
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestUpdateMaxTokenAutoGroupsAcceptsAnyPositiveInteger(t *testing.T) {
+	original := GetMaxTokenAutoGroups()
+	t.Cleanup(func() {
+		require.NoError(t, UpdateMaxTokenAutoGroups(fmt.Sprintf("%d", original)))
+	})
+
+	require.NoError(t, UpdateMaxTokenAutoGroups("123456"))
+	assert.Equal(t, 123456, GetMaxTokenAutoGroups())
+}
+
+func TestUpdateMaxTokenAutoGroupsRejectsInvalidValuesWithoutChangingState(t *testing.T) {
+	original := GetMaxTokenAutoGroups()
+	for _, value := range []string{"", "0", "-1", "1.5", "not-a-number"} {
+		t.Run(value, func(t *testing.T) {
+			assert.Error(t, UpdateMaxTokenAutoGroups(value))
+			assert.Equal(t, original, GetMaxTokenAutoGroups())
+		})
+	}
+}