fix(swap): 修复复利平仓时已结利息扣除计算问题

- 修改 CalcCompoundUnwind 方法添加 closePercent 参数用于部分平仓场景
- 更新复利平仓逻辑，将已结利息按平仓比例进行缩放扣除
- 添加部分平仓测试用例验证已结利息按比例扣除的正确性
- 修复了全部已结利息在部分平仓时被全额扣除的问题

UnitTestProject/Modules/SwapModule/ConsumedInterestScenarioTest.cs

@@ -108,13 +108,13 @@ namespace YLErp.Modules.SwapModule
         }
 
         /// <summary>调用 GetInterests 获取复利利息（统一调用入口，settment:false走盘中平仓路径）</summary>
-        private static swap_flow_event CalcCompoundUnwind(StubSwapDealService service, DateTime unwindDate)
+        private static swap_flow_event CalcCompoundUnwind(StubSwapDealService service, DateTime unwindDate, decimal closePercent = 1m)
         {
             var td = CreateTrade();
             var position = CreateCompoundPosition();
             var interests = service.GetInterests(td, td.trade_extend, unwindDate, unwindDate,
                 new List<eod_swap_position>(), new List<swap_position> { position },
-                Principal, Principal, Principal, Principal, 1m,
+                Principal, Principal, Principal, Principal, closePercent,
                 (int)SwapEventTypeEnum.平仓, false, false, Principal, Principal,
                 add: false, settment: false, newCalcLast: false);
             Assert.AreEqual(1, interests.Count);
@@ -246,5 +246,19 @@ namespace YLErp.Modules.SwapModule
                 $"全部已结再平仓利息应≈0（实际={result.InterestAmount:F6}），不应为负");
             Console.WriteLine($"全部已结平仓≈0（{result.InterestAmount:F6}）✅");
         }
+
+        [TestMethod]
+        public void CI_005_partialClose_scalesConsumedInterest()
+        {
+            var unwindDate = StartDate.AddDays(10);
+            const decimal closePercent = 0.4m;
+            const decimal consumed = 100m;
+
+            var baseline = CalcCompoundUnwind(CreateService(0m), unwindDate, closePercent).InterestAmount;
+            var result = CalcCompoundUnwind(CreateService(consumed), unwindDate, closePercent).InterestAmount;
+
+            AssertDecimal(baseline - consumed * closePercent, result,
+                $"partial close should deduct consumed interest by closePercent ({closePercent})");
+        }
     }
 }