fix(warehouse): 修复库存商品总价计算逻辑

- 在更新库存商品数量时，增加了对商品采购价的判断
- 当采购价小于等于 0 时，将总价设置为 0，否则正常计算总价

app/admin/logic/warehouse_product/WarehouseProductLogic.php

@@ -48,9 +48,10 @@ class WarehouseProductLogic extends BaseLogic
                         if (!$storeProduct) {
                             throw new BusinessException('商品不存在');
                         }
-                        $total_price = bcmul($after_nums, $storeProduct['purchase'], 2);
                         if($storeProduct['purchase']<=0){
                             $total_price=0;
+                        }else{
+                            $total_price = bcmul($after_nums, $storeProduct['purchase'], 2);
                         }
                         WarehouseProductStorege::update(['nums' => $after_nums, 'total_price' => $total_price], ['id' => $storege['id']]);
                     }