refactor(pricing): 调整优惠优先级顺序

-

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

@@ -34,7 +34,7 @@ public class CouponDiscountProvider implements IDiscountProvider {
     
     @Override
     public int getPriority() {
-        return 80; // 优惠券优先级为80，低于券码的100
+        return 60; // 优惠券优先级最低
     }
     
     @Override

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

@@ -31,7 +31,7 @@ public class OnePricePurchaseDiscountProvider implements IDiscountProvider {
     
     @Override
     public int getPriority() {
-        return 60; // 中等优先级，在券码和优惠券之间
+        return 120; // 最高优先级，一口价优先应用
     }
     
     @Override

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

@@ -36,7 +36,7 @@ public class VoucherDiscountProvider implements IDiscountProvider {
     
     @Override
     public int getPriority() {
-        return 100; // 券码优先级最高
+        return 80; // 券码优先级第三，仅次于一口价和打包购买
     }
     
     @Override