refactor(ai): 重构AI接口算力点扣费逻辑并添加失败返还机制

- 移除预检查算力点步骤，改为请求前预扣算力点
- 添加请求失败时自动返还算力点的功能
- 修改copyAIResponse函数参数以支持失败回调处理
- 在响应状态异常时也执行算力点返还操作
- 从auth服务中移除EnsureUserCredits方法
- 新增RefundUserCredits方法用于返还用户算力点
- 添加AI_REFUND算力点日志类型常量
- 更新算力点日志类型说明及展示标签

service/auth.go

@@ -318,20 +318,6 @@ func AdjustUserCredits(id string, credits int) (model.User, error) {
 	return user, err
 }
 
-func EnsureUserCredits(userID string, credits int) error {
-	if credits <= 0 {
-		return nil
-	}
-	ok, err := repository.HasUserCredits(userID, credits)
-	if err != nil {
-		return err
-	}
-	if !ok {
-		return safeMessageError{message: "算力点不足"}
-	}
-	return nil
-}
-
 func ConsumeUserCredits(userID string, modelName string, credits int, path string) error {
 	if credits <= 0 {
 		return nil
@@ -357,6 +343,31 @@ func ConsumeUserCredits(userID string, modelName string, credits int, path strin
 	return err
 }
 
+func RefundUserCredits(userID string, modelName string, credits int, path string) error {
+	if credits <= 0 {
+		return nil
+	}
+	user, ok, err := repository.RefundUserCredits(userID, credits, now())
+	if err != nil {
+		return err
+	}
+	if !ok {
+		return safeMessageError{message: "用户不存在"}
+	}
+	extra, _ := json.Marshal(map[string]string{"model": modelName, "path": path})
+	_, err = repository.SaveCreditLog(model.CreditLog{
+		ID:        newID("credit"),
+		UserID:    userID,
+		Type:      model.CreditLogTypeAIRefund,
+		Amount:    credits,
+		Balance:   user.Credits,
+		Remark:    "模型调用失败返还 " + modelName,
+		Extra:     string(extra),
+		CreatedAt: now(),
+	})
+	return err
+}
+
 func ListCreditLogs(q model.Query) (model.CreditLogList, error) {
 	logs, total, err := repository.ListCreditLogs(q)
 	if err != nil {