refactor(return-leg): QuantityRollforward 改名 QtyRollforward

代码里统一用 Qty 表示数量, 命名更简洁。
文件/类/测试类同步改名: Quantity→Qty。

UnitTestProject/Modules/SwapModule/ReturnLegs/QtyRollforwardTest.cs

@@ -6,58 +6,55 @@ namespace UnitTestProject.Modules.SwapModule.ReturnLegs
     /// 标的端数量递推测试。验证开仓/平仓/公司行为场景下数量正确推进。
     /// </summary>
     [TestClass]
-    public class QuantityRollforwardTest
+    public class QtyRollforwardTest
     {
         [TestMethod]
         public void 无交易_数量不变()
         {
-            Assert.AreEqual(1000m, QuantityRollforward.Calc(1000m, 0m, 0m));
+            Assert.AreEqual(1000m, QtyRollforward.Calc(1000m, 0m, 0m));
         }
 
         [TestMethod]
         public void 开仓_数量增加()
         {
-            Assert.AreEqual(1500m, QuantityRollforward.Calc(1000m, 500m, 0m));
+            Assert.AreEqual(1500m, QtyRollforward.Calc(1000m, 500m, 0m));
         }
 
         [TestMethod]
         public void 平仓_数量减少()
         {
-            Assert.AreEqual(600m, QuantityRollforward.Calc(1000m, 0m, 400m));
+            Assert.AreEqual(600m, QtyRollforward.Calc(1000m, 0m, 400m));
         }
 
         [TestMethod]
         public void 开仓加平仓_净值()
         {
-            Assert.AreEqual(1200m, QuantityRollforward.Calc(1000m, 500m, 300m));
+            Assert.AreEqual(1200m, QtyRollforward.Calc(1000m, 500m, 300m));
         }
 
         [TestMethod]
         public void 全平_数量归零()
         {
-            Assert.AreEqual(0m, QuantityRollforward.Calc(1000m, 0m, 1000m));
+            Assert.AreEqual(0m, QtyRollforward.Calc(1000m, 0m, 1000m));
         }
 
         [TestMethod]
         public void 超额平仓_不低于零()
         {
-            Assert.AreEqual(0m, QuantityRollforward.Calc(1000m, 0m, 1500m));
+            Assert.AreEqual(0m, QtyRollforward.Calc(1000m, 0m, 1500m));
         }
 
         [TestMethod]
         public void 公司行为送股_数量增加_默认不影响()
         {
-            // 默认 corpActionDeltaQty=0, 行为不变
-            Assert.AreEqual(1000m, QuantityRollforward.Calc(1000m, 0m, 0m));
-            // 送股 10%: 1000 × 10% = 100
-            Assert.AreEqual(1100m, QuantityRollforward.Calc(1000m, 0m, 0m, corpActionDeltaQty: 100m));
+            Assert.AreEqual(1000m, QtyRollforward.Calc(1000m, 0m, 0m));
+            Assert.AreEqual(1100m, QtyRollforward.Calc(1000m, 0m, 0m, corpActionDeltaQty: 100m));
         }
 
         [TestMethod]
         public void 公司行为拆股_数量翻倍()
         {
-            // 1拆2: 数量翻倍, corpActionDeltaQty = 当前数量
-            Assert.AreEqual(2000m, QuantityRollforward.Calc(1000m, 0m, 0m, corpActionDeltaQty: 1000m));
+            Assert.AreEqual(2000m, QtyRollforward.Calc(1000m, 0m, 0m, corpActionDeltaQty: 1000m));
         }
     }
 }