fix(coupon): 修复优惠券适用商品类型为空时的处理逻辑

- 添加空数组检查，当适用商品类型为空时不进行过滤
- 修复商品类型为空时直接返回全部商品总价的逻辑
- 保持原有商品类型过滤功能的完整性

src/main/java/com/ycwl/basic/pricing/service/impl/CouponServiceImpl.java

@@ -125,6 +125,10 @@ public class CouponServiceImpl implements ICouponService {
                 List<String> applicableProductTypes = objectMapper.readValue(
                     coupon.getApplicableProducts(), new TypeReference<List<String>>() {});
 
+                // 空数组表示不限制商品类型，适用于所有商品
+                if (applicableProductTypes == null || applicableProductTypes.isEmpty()) {
+                    // 不过滤，使用全部商品
+                } else {
                     discountableProducts = products.stream()
                         .filter(product -> applicableProductTypes.contains(product.getProductType().getCode()))
                         .toList();
@@ -132,6 +136,7 @@ public class CouponServiceImpl implements ICouponService {
                     if (discountableProducts.isEmpty()) {
                         return false;
                     }
+                }
             } catch (Exception e) {
                 log.error("解析适用商品类型失败", e);
                 return false;
@@ -198,6 +203,13 @@ public class CouponServiceImpl implements ICouponService {
             List<String> applicableProductTypes = objectMapper.readValue(
                     coupon.getApplicableProducts(), new TypeReference<List<String>>() {});
 
+            // 空数组表示不限制商品类型，返回所有商品总价
+            if (applicableProductTypes == null || applicableProductTypes.isEmpty()) {
+                return products.stream()
+                        .map(ProductItem::getSubtotal)
+                        .reduce(BigDecimal.ZERO, BigDecimal::add);
+            }
+
             // 计算适用商品的总价
             return products.stream()
                     .filter(product -> applicableProductTypes.contains(product.getProductType().getCode()))