fix(swap): 修复利息互换平仓结算中的尾差处理和本金计算问题

- 修复ExecuteSaveAutoEodInterestPosition方法参数传递，添加lastEodSwap、posiLongNotional和orginPv参数
- 修正平仓利息计算逻辑，区分手动结算和平仓后自动结算的利息处理
- 新增ResolveUnwindPreviousNotional静态方法，优化平仓前本金计算逻辑
- 修复部分平仓后利息累积边界问题，确保仅从上次EOD快照后开始计算
- 完善自动结算利息的四舍五入处理，避免精度丢失
- 修正支付端方向符号应用，确保方向只应用一次
- 更新TdInterestPrincipal计算逻辑，处理不同利息模式下的本金赋值
- 修复TdCloseInterest计算，合并手动和自动结算利息金额
- 优化InterestIncomeSum计算，正确处理结算后剩余未实现利息

YLErpDAL/Modules/SwapModule/SwapEodPositionService.cs

@@ -1161,13 +1161,7 @@ namespace YLErp.Modules.SwapModule
             }
 
             var tradeExtend = td.trade_extend.ExtendObj;
-            decimal oriPosiNotionalValue = posiLongNotional + posiShortNational;
-            decimal posiNotionalValue = oriPosiNotionalValue;
-            bool longShort = td.StructureType == ClientMarginTypeEnum.多空组合.ToString();
-            if (lastEodSwap != null)
-            {
-                posiNotionalValue = lastEodSwap.NotionalValue;
-            }
+            decimal posiNotionalValue = posiLongNotional + posiShortNational;
             decimal closePercent = 1;
             decimal ratio = position.InterestDirection == (int)SwapDirectionEnum.收取 ? 1m : -1m;//收取为正，支付为负
             if (marginTypes.Contains(position.InterestMode))
@@ -1293,10 +1287,11 @@ namespace YLErp.Modules.SwapModule
             var lastInterestFeeSum = eodPayPosition?.InterestFeeSum ?? 0m;
             var lastRealizedInterest = eodPayPosition?.RealizedInterest ?? 0m;
             var lastRealizedInterestFee = eodPayPosition?.RealizedInterestFee ?? 0m;
-            eodPayPosition = new eod_swap_position();
+            // 保留上一日日终标识和计息上下文，部分平仓只从 ValueDate 之后续算，不能重置到交易起始日。
+            eodPayPosition = eodPayPosition?.Clone() ?? new eod_swap_position();
             eodPayPosition.ClientId = td.ClientId;
             eodPayPosition.SwapTradeId = td.id;
-            // CalcSwapInterests 按 PositionId 查找上一日日终；id 仍保持 0，沿用盘中平仓的原有计息日期语义。
+            // CalcSwapInterests 按 PositionId 匹配上一日日终。
             eodPayPosition.PositionId = position.id;
             eodPayPosition.PosiStartDate = td.StartDate.Value;
             eodPayPosition.PosiMatuirityDate = td.ExerciseDate.Value;
@@ -1338,7 +1333,17 @@ namespace YLErp.Modules.SwapModule
             preEodPositions.Add(eodPayPosition);
             var interests = CalcSwapInterests(td, td.trade_extend, valueDate, valueDate, preEodPositions, positions, posiNotionalValue, posiLongNotional, posiShortNational, closeNational, 1, eventType, false, true, grossPrice, orginPv, true, settment: false, newCalcLast: true);
             decimal TdInterestAmount = interests.Sum(x => x.TdInterestAmount);
-            decimal InterestAmount = interests.Sum(x => x.InterestAmount);
+            decimal interestAmountBeforeSettlement = interests.Sum(x => x.InterestAmount);
+            decimal manualSettledInterestAmount = flowEvents.Sum(x => x.InterestAmount);
+            decimal autoSettledInterestAmount = 0m;
+            if (autoSwap && interests.Count > 0)
+            {
+                autoSettledInterestAmount = RoundMoney(interestAmountBeforeSettlement - manualSettledInterestAmount);
+                var autoInterest = interests[0];
+                autoInterest.InterestAmount = autoSettledInterestAmount;
+                autoInterest.InterestClosePnL = autoSettledInterestAmount
+                    * (autoInterest.InterestDirection == (int)SwapDirectionEnum.收取 ? 1m : -1m);
+            }
             newEodPayPosition.ValueDate = valueDate;
             newEodPayPosition.PositionId = position.id;
             UpdateDbOption(newEodPayPosition);
@@ -1359,7 +1364,9 @@ namespace YLErp.Modules.SwapModule
             newEodPayPosition.interest_rest_days = position.interest_rest_days;
             newEodPayPosition.interest_rule = position.interest_rule;
             //利息端估值用信息
-            newEodPayPosition.TdInterestPrincipal = interests.Count > 0 ? interests.First().InterestPrincipal : 0;
+            newEodPayPosition.TdInterestPrincipal = position.InterestMode == (int)InterestModeEnum.标的期初全价
+                ? posiNotionalValue
+                : interests.Count > 0 ? interests.First().InterestPrincipal : 0;
             if (interval != null)
             {
                 newEodPayPosition.TdInterestRate = interval.Rate;
@@ -1371,7 +1378,7 @@ namespace YLErp.Modules.SwapModule
             //当日已实现，平仓时已处理
             newEodPayPosition.TdInterestFee = flowEvents.Sum(s => s.InterestFee);
             newEodPayPosition.TdCloseInterestFee = newEodPayPosition.TdInterestFee;
-            newEodPayPosition.TdCloseInterest = flowEvents.Sum(s => s.InterestClosePnL);
+            newEodPayPosition.TdCloseInterest = manualSettledInterestAmount + autoSettledInterestAmount;
             var intersetAcmount = newEodPayPosition.TdInterestPrincipal * (newEodPayPosition.TdInterestRate + newEodPayPosition.FloatRate);
             if (position.IsAnnualized)
             {
@@ -1390,7 +1397,8 @@ namespace YLErp.Modules.SwapModule
             }
             else
             {
-                newEodPayPosition.InterestIncomeSum = InterestAmount;
+                newEodPayPosition.InterestIncomeSum = RoundEodInterest(
+                    interestAmountBeforeSettlement - newEodPayPosition.TdCloseInterest);
                 newEodPayPosition.InterestFeeSum = eodPayPosition.InterestFeeSum + newEodPayPosition.TdInterestFee - newEodPayPosition.TdCloseInterestFee;
             }
             //持仓内容-利息腿-损益统计(本方视角）