test: 补全 SaveAutoSwapDeal 的测试 seam——修复6个AS_*测试失败

- SwapEodPositionService: AddSwapEvent 虚方法(已存在)替换 line 741 的 new SwapEventService 直调

- SwapEodPositionService: 新增 PersistFlowEvent 虚方法，替换 line 749/760 的 DbContext.swap_flow_event.Add 直调

- TestableSwapEodPositionService: PersistFlowEvent 改为 override

- BondTrsAutoSwapScenarioTest.AutoSwapEodService: override PersistFlowEvent 同步到 PersistedFlowEvents

测试: 511→517 通过，7→0 失败

YLErpDAL/Modules/SwapModule/SwapEodPositionService.cs

@@ -134,6 +134,12 @@ namespace YLErp.Modules.SwapModule
             return new SwapEventService(this).AddSwapEventDate(tradeDate, swapTradeId, eventType, data, clientCashId, save, reason);
         }
 
+        /// <summary>持久化互换流水事件（生产: DbContext.swap_flow_event.Add；测试: 收集到列表）</summary>
+        protected virtual void PersistFlowEvent(swap_flow_event flowEvent)
+        {
+            DbContext.swap_flow_event.Add(flowEvent);
+        }
+
         /// <summary>在事务中执行（生产: BeginTransaction/Commit/Rollback；测试: 直接执行不包事务）</summary>
         protected virtual void ExecuteInTransaction(Action action)
         {
@@ -738,24 +744,26 @@ namespace YLErp.Modules.SwapModule
 
             unwindData.ClientCashIds = clientCashIds;
             string data = JsonConvert.SerializeObject(unwindData);
-            var swapEvent = new SwapEventService(this).AddSwapEventDate(unwindData.ValueDate, unwindData.SwapTradeId, (int)SwapEventTypeEnum.自动互换, data, clientCashId, true, "系统操作-自动互换");//将互换总额存入事件
+            // 走虚方法 AddSwapEvent（与 ComposePage:800 一致），让测试可 override 捕获事件；
+            // 默认实现仍是 new SwapEventService(this).AddSwapEventDate，生产行为不变。
+            var swapEvent = AddSwapEvent(unwindData.ValueDate, unwindData.SwapTradeId, (int)SwapEventTypeEnum.自动互换, data, clientCashId, true, "系统操作-自动互换");//将互换总额存入事件
             if (flowEvents!=null)
             {
                 flowEvents.ForEach(x =>
                 {
                     x.EventId = swapEvent.id;
-                    DbContext.swap_flow_event.Add(x);
+                    PersistFlowEvent(x);
                 });
                 UpdateInitalPostion(flowEvents, td.id);
             }
-           
+
             // 保存分红事件
             if (dividendEvents != null)
             {
                 dividendEvents.ForEach(x =>
                 {
                     x.EventId = swapEvent.id;
-                    DbContext.swap_flow_event.Add(x);
+                    PersistFlowEvent(x);
                 });
                 UpdateInitalPostion(dividendEvents, td.id);
             }