feat(channel): 添加抖音币充值功能

- 新增 dy 方法实现抖音币充值
- 调整参数检查逻辑，支持 api_product 参数
- 计算充值金额为 cash 和 num 的乘积

app/channel/service/system/Jiujiufu.php

@@ -152,6 +152,23 @@ class Jiujiufu extends Core
         return $this->submit($param, $check);
     }
 
+    #抖音币充值
+    public function dy($param){
+        $check = array
+        (
+            'account' => 'account',
+            'cash' => 'cash',
+            'api_product' => 'api_product',
+        );
+        if(isset($param['api_product'])){
+            unset($check['product']);
+            $check['api_product'] = 'api_product';
+        }
+        $param['api_product'] = 'dbcz';
+        $param['cash'] = $param['cash'] * $param['num']??1;
+        return $this->submit($param, $check);
+    }
+
     #获取手机号码
     public function getMobileCode($param)
     {