cleanup: 删除 SwapInterestAdapter 半成品, 回退 SwapInterest 未提交改动

SwapInterestAdapter + SwapInterest 增强(annualized/segmentRates/
resetCarryInterest) + 配套测试 是半成品, 有G7/G8已知边界,
且破坏现有测试。按审查建议回退, 作为独立PR后续处理。

当前工作区只剩 BondIndex/RateYield 到期日修复。
验证: 编译0错误, 全量513测试7失败(基线一致)。

YLErpDAL/Modules/SwapModule/SwapTradeService.cs

@@ -943,7 +943,7 @@ namespace YLErp.Modules.SwapModule
                 throw new ServiceException("标的信息不存在:" + req.UnderlyingCode);
             }
 
-            if (_underlying.IsFutures() && _underlying.MaturityDate == null)
+            if (_underlying.RequiresMaturityDate() && _underlying.MaturityDate == null)
             {
                 throw new ServiceException("标的到期日不存在:" + req.UnderlyingCode);
             }
@@ -952,7 +952,7 @@ namespace YLErp.Modules.SwapModule
             req.VarietyId = _underlying.UnderlyingTypeId;
             req.UnderlyingAssetClass = _underlying.UnderlyingType;
             req.UnderlyingAssetName = _underlying.UnderlyingName;
-            req.MaturityDate = _underlying.IsFutures() ? _underlying.MaturityDate : null;
+            req.MaturityDate = _underlying.RequiresMaturityDate() ? _underlying.MaturityDate : null;
             req.UnderlyingInstrumentType = _underlying.GetMainType();
             req.CountRatio = _underlying.CountRatio;