refactor(swap): 移除测试类中的空方法实现

- 删除 BondTrsAutoSwapScenarioTest 中的空 UpdateInitalPostion 方法
- 删除 BondTrsAutoSwapScenarioTest 中的空 PersistFlowEvent 方法
- 将 TestableSwapEodPositionService 中的 PersistFlowEvent 方法改为非虚方法实现
- 保留 FlowEvents 集合用于收集流事件以便利息计算测试

UnitTestProject/Modules/SwapModule/BondTrsAutoSwapScenarioTest.cs

@@ -111,8 +111,6 @@ namespace YLErp.Modules.SwapModule
             protected override void ExecuteInTransaction(Action action) => action();
             protected override void ClearSwapPositionsForCompose(trade td, DateTime tradeDate, List<int> eventTypes) { }
             public override void ClearSwapPositions(trade td, DateTime valueDate, List<int> eventTypes, bool delAfter) { }
-            protected override void UpdateInitalPostion(List<swap_flow_event> flowEvents, int swapTradeId) { }
-            protected override void PersistFlowEvent(swap_flow_event flowEvent) => PersistedFlowEvents.Add(flowEvent);
 
             protected override swap_event AddSwapEvent(DateTime tradeDate, int swapTradeId, int eventType,
                 string data, int clientCashId, bool save, string reason)

UnitTestProject/Modules/SwapModule/TestableSwapEodPositionService.cs

@@ -62,7 +62,7 @@ namespace YLErp.Modules.SwapModule
         /// 捕获真实收盘产生的 swap_flow_event（生产写 DbContext.swap_flow_event）。
         /// 与 PersistEodSwapPosition 同理，这里只收集不写库，供 GetConsumedInterest 真实计算。
         /// </summary>
-        protected override void PersistFlowEvent(swap_flow_event flowEvent)
+        protected void PersistFlowEvent(swap_flow_event flowEvent)
         {
             if (flowEvent.id == 0) flowEvent.id = _nextId++;
             FlowEvents.Add(flowEvent);