fix(pricing): 修复升级检查中的支付金额处理逻辑

- 移除 resolvePaidAmount 方法中对 purchasedDetails 的依赖
- 添加支付金额为空时的异常抛出机制
- 在升单结果中添加补差价金额的判断逻辑
- 更新文档中标注支付金额为必填字段
- 优化打包优惠计算中的补差价处理流程

src/main/java/com/ycwl/basic/pricing/CLAUDE.md

@@ -616,14 +616,14 @@ UpgradeCheckResult checkUpgrade(UpgradeCheckRequest request);
 - `scenicId`: 景区ID
 - `purchasedProducts`: 已购商品列表
 - `intendingProducts`: 待购商品列表
-- `paidAmount`: 已支付金额（内部代码传入，前端不必传）
+- `paidAmount`: 已支付金额（内部代码传入，前端不必传；**必填**，为空直接报错）
 
 #### 检测流程
 1. **商品规范化**: 对已购和待购商品进行规范化处理
 2. **价格汇总**: 分别计算已购和待购商品的总价格，并合并已支付金额
 3. **一口价评估**: 判断合并商品是否满足一口价条件
 4. **打包优惠评估**: 检测是否满足打包购买优惠条件
-5. **结果汇总**: 生成升单检测结果和建议
+5. **结果汇总**: 生成升单检测结果和建议（补差价 <= 0 视为不可升单）
 
 #### 响应结果 (UpgradeCheckResult)
 - `summary`: 价格汇总信息（包含已支付金额）

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

@@ -193,7 +193,7 @@ public class PriceCalculationServiceImpl implements IPriceCalculationService {
         combinedProducts.addAll(intendingProducts);
         PriceDetails combinedDetails = calculateProductsPriceWithOriginal(combinedProducts, scenicId);
 
-        BigDecimal paidAmount = resolvePaidAmount(request, purchasedDetails);
+        BigDecimal paidAmount = resolvePaidAmount(request);
         BigDecimal currentTotalAmount = calculateCurrentTotalAmount(paidAmount, intendingDetails);
 
         UpgradePriceSummary priceSummary = buildPriceSummary(purchasedDetails, intendingDetails, combinedDetails, paidAmount);
@@ -480,6 +480,10 @@ public class PriceCalculationServiceImpl implements IPriceCalculationService {
         }
 
         BigDecimal discountAmount = normalizedCurrentTotal.subtract(normalizedBundlePrice);
+        BigDecimal supplementAmount = calculateSupplementAmount(normalizedBundlePrice, normalizedPaidAmount);
+        if (supplementAmount.compareTo(BigDecimal.ZERO) <= 0) {
+            return result;
+        }
         
         result.setApplicable(true);
         result.setBundleConfigId(bundleConfig.getId());
@@ -488,7 +492,7 @@ public class PriceCalculationServiceImpl implements IPriceCalculationService {
         result.setScenicId(bundleConfig.getScenicId());
         result.setBundlePrice(normalizedBundlePrice);
         result.setDiscountAmount(discountAmount);
-        result.setEstimatedFinalAmount(calculateSupplementAmount(normalizedBundlePrice, normalizedPaidAmount));
+        result.setEstimatedFinalAmount(supplementAmount);
         return result;
     }
     
@@ -525,6 +529,11 @@ public class PriceCalculationServiceImpl implements IPriceCalculationService {
             return result;
         }
 
+        BigDecimal supplementAmount = calculateSupplementAmount(targetTotal, normalizedPaidAmount);
+        if (supplementAmount.compareTo(BigDecimal.ZERO) <= 0) {
+            return result;
+        }
+
         result.setApplicable(true);
         result.setBundleConfigId(bestDiscount.getBundleConfigId());
         result.setBundleName(bestDiscount.getBundleName());
@@ -534,7 +543,7 @@ public class PriceCalculationServiceImpl implements IPriceCalculationService {
         result.setDiscountAmount(normalizedDiscount);
         result.setMinQuantity(bestDiscount.getMinQuantity());
         result.setMinAmount(bestDiscount.getMinAmount());
-        result.setEstimatedFinalAmount(calculateSupplementAmount(targetTotal, normalizedPaidAmount));
+        result.setEstimatedFinalAmount(supplementAmount);
         return result;
     }
     
@@ -592,10 +601,10 @@ public class PriceCalculationServiceImpl implements IPriceCalculationService {
         return configScenicId.equals(String.valueOf(scenicId));
     }
 
-    private BigDecimal resolvePaidAmount(UpgradeCheckRequest request, PriceDetails purchasedDetails) {
+    private BigDecimal resolvePaidAmount(UpgradeCheckRequest request) {
         BigDecimal paidAmount = request != null ? request.getPaidAmount() : null;
-        if (paidAmount == null && purchasedDetails != null) {
-            paidAmount = purchasedDetails.getTotalAmount();
+        if (paidAmount == null) {
+            throw new PriceCalculationException("已支付金额不能为空");
         }
         return normalizeAmount(paidAmount);
     }