fix(order): 修复发货单号生成方法

- 将 SequenceUtils.nextIdDateTimePadded 方法替换为 generateOrderCode 方法
- 发货单号前缀从空字符串改为 "YO" 以符合业务规范

ruoyi-modules/ruoyi-order/src/main/java/org/dromara/order/service/impl/OrderDeliverServiceImpl.java

@@ -216,7 +216,7 @@ public class OrderDeliverServiceImpl extends ServiceImpl<OrderDeliverMapper, Ord
             Long orderId = bo.getOrderId();
 
             // 1. 生成发货单号
-            bo.setDeliverCode(SequenceUtils.nextIdDateTimePadded(""));
+            bo.setDeliverCode(SequenceUtils.generateOrderCode("YO"));
 
             // 2. 计算本次发货总数
             long currentDeliverQty = bo.getOrderDeliverProducts().stream()