feat(order): 优化预付款字段转换逻辑

- 支持多种输入格式（是/否、Y/N、Yes/No）
- 添加输入值空值检查和空格处理
- 实现不区分大小写的英文匹配
- 统一转换为char(1)格式存储

src/main/java/com/xujie/modules/order/service/Impl/PODetailServiceImpl.java

@@ -254,10 +254,17 @@ public class PODetailServiceImpl extends ServiceImpl<PODetailMapper, PODetail> i
                 poDetailVo.setPlanner(excelDTO.getPlanner());
                 poDetailVo.setRemark(excelDTO.getRemark());
 
-                // char(1) 修复
-                poDetailVo.setAdvancePayment(
-                        "是".equals(excelDTO.getAdvancePayment()) ? "Y" : "N"
-                );
+                // char(1) 字段转换：支持多种输入格式（是/否、Y/N、Yes/No）
+                String advancePaymentInput = excelDTO.getAdvancePayment();
+                boolean needAdvance = false;
+                if (advancePaymentInput != null && !advancePaymentInput.trim().isEmpty()) {
+                    String trimmed = advancePaymentInput.trim();
+                    // 支持中文"是"、英文"Y"或"Yes"（不区分大小写）
+                    needAdvance = "是".equals(trimmed) 
+                               || "Y".equalsIgnoreCase(trimmed) 
+                               || "YES".equalsIgnoreCase(trimmed);
+                }
+                poDetailVo.setAdvancePayment(needAdvance ? "Y" : "N");
 
                 try {
                     if (excelDTO.getWantReceiveDate() != null && !excelDTO.getWantReceiveDate().isEmpty()) {