优化收益互换方向判断逻辑，移除冗余方法

Plugins/YLErp.Plugins.GuoLian/DocumentGenerator/TradeConfirmationGenerator.cs

@@ -54,8 +54,11 @@ namespace YLErp.Plugins.GuoLian.DocumentGenerator
             var trade = Context.Trade;
             var underlying = Context.GetTradeUnderlying();
 
-            // 判断看多/看空方向
-            bool isLong = IsLongPosition(trade);
+            // 判断看多/看空方向（通过持仓方向判断：PositionType: 1=多头/看多，2=空头/看空）
+            var swapPosition = Context.GetSwapPositions(trade.id, true)
+                .Where(x => x.PositionType == (int)PositionTypeFlag.Long || x.PositionType == (int)PositionTypeFlag.Short)
+                .FirstOrDefault();
+            bool isLong = swapPosition?.PositionType == (int)PositionTypeFlag.Long;
 
             // 判断标的类型（债券ETF vs 现券）
             bool isEtf = IsBondEtf(underlying?.UnderlyingCode ?? string.Empty);
@@ -74,15 +77,6 @@ namespace YLErp.Plugins.GuoLian.DocumentGenerator
             return Path.Combine(GlobalConfig.PluginFolder, "App_Docs\\contract_template", templateName);
         }
 
-        /// <summary>
-        /// 判断是否为多头/看多方向
-        /// </summary>
-        private bool IsLongPosition(OtcTradeBase trade)
-        {
-            // 通过BuySell判断：买入=看多，卖出=看空
-            return trade.BuySell == "买入";
-        }
-
         /// <summary>
         /// 判断是否为债券ETF
         /// - .SH后缀且511开头 -> 债券ETF