fix(charging): 修正服务费用计算时的小数舍入方式

- 将服务费用乘积后的舍入方式由四舍五入改为向下舍入
- 修正了ChargingReceptionServiceImpl中计算服务费的精度处理
- 确保服务费用计算结果保持一致性和准确性

src/main/java/com/zsElectric/boot/charging/service/impl/ChargingReceptionServiceImpl.java

@@ -247,7 +247,7 @@ public class ChargingReceptionServiceImpl implements ChargingReceptionService {
                         .eq(PolicyFee::getPeriodFlag, Integer.parseInt(itemFlag))
                         .last("LIMIT 1"));
                 BigDecimal opFee = policyFee.getOpFee();
-                serviceFee = serviceFee.add(opFee.multiply(new BigDecimal(detailPower))).setScale(2, RoundingMode.HALF_UP);
+                serviceFee = serviceFee.add(opFee.multiply(new BigDecimal(detailPower))).setScale(2, RoundingMode.DOWN);
             }
 
             chargeOrderInfo.setRealServiceCost(serviceFee);