feat(subscription): add support for wallet overflow and downgrade group functionality in subscription plans

service/billing_session.go

@@ -425,7 +425,15 @@ func NewBillingSession(c *gin.Context, relayInfo *relaycommon.RelayInfo, preCons
 		session, apiErr := trySubscription()
 		if apiErr != nil {
 			if apiErr.GetErrorCode() == types.ErrorCodeInsufficientUserQuota {
-				return tryWallet()
+				// 仅当用户的活跃订阅允许钱包回退时才回退到钱包，否则返回订阅额度不足错误
+				allowOverflow, overflowErr := model.UserActiveSubscriptionsAllowWalletOverflow(relayInfo.UserId)
+				if overflowErr != nil {
+					return nil, types.NewError(overflowErr, types.ErrorCodeQueryDataError, types.ErrOptionWithSkipRetry())
+				}
+				if allowOverflow {
+					return tryWallet()
+				}
+				return nil, apiErr
 			}
 			return nil, apiErr
 		}