refactor(accrual): EOD去退化差分——删除baseNotional死参数

EOD路径 orginPv≡posiPrincipal(调用点line1091/1096实证)，notional==baseNotional恒成立，
差分项 notional-baseNotional 恒为0，baseNotional 是死参数。

简化:
- AccrueSimpleEod: 删 notional+baseNotional 两参数，basis=priorNotional 直赋值
- AccrueCompoundEod: 删 baseNotional 参数，非重置日 basis=priorNotional
- SimpleEodBasis 整个删除(不再需要)
- CompoundEodBasis 去掉 baseNotional 参数
- EodContext trace 去掉 baseNotional
- 差分注释块删除(EOD不再有差分)

差分逻辑 notional-baseNotional 只该存在于 unwind 专用路径(Period函数本就没有baseNotional)
净减20行(18增/38删)，SwapModule零回归(7基线/508通过/8跳过)

UnitTestProject/Modules/SwapModule/Accrual/CompoundEodShadowTest.cs

@@ -100,7 +100,7 @@ namespace UnitTestProject.Modules.SwapModule.Accrual
             var policy = new AccrualPolicy(AccrualBoundary.Both, true, 7, AnnualDays, true);
             var remainingPercent = Math.Max(0m, Math.Min(1m, Notional / Notional));
             var result = FundingLegAccrual.AccrueCompoundEod(
-                50_000m, Notional, Notional, 1m, Notional, rate, policy,
+                50_000m, Notional, Notional, 1m, rate, policy,
                 isResetDay: true, remainingPercent, EodDate);
 
             Console.WriteLine($"重置日: 旧 InterestAmount={oldInterest} Td={oldTd}");
@@ -132,7 +132,7 @@ namespace UnitTestProject.Modules.SwapModule.Accrual
             var rate = FundingLegRate.Fixed(FixedRate);
             var policy = new AccrualPolicy(AccrualBoundary.Both, true, 7, AnnualDays, true);
             var result = FundingLegAccrual.AccrueCompoundEod(
-                30_000m, Notional, Notional, 1m, Notional, rate, policy,
+                30_000m, Notional, Notional, 1m, rate, policy,
                 isResetDay: false, 0m, nonResetDate);
 
             Console.WriteLine($"非重置日: 旧 InterestAmount={oldInterest} Td={oldTd}");