fix(SwapTrade2): 到期日期默认值置空并限制不可早于成交/开始日期

- 移除新增交易时到期日期的默认值（原StartDate+14天），改为空白由用户手工填写
- 到期日期选择器增加mindate限制，不可选择早于成交日期和开始日期的日期
- 联动修正：成交日期或开始日期变化时同步刷新到期日期下限

YLErpWeb/Controllers/SwapTrade2Controller.cs

@@ -78,7 +78,6 @@ namespace YLErp.Web.Controllers
                     InitialMargin = 0
                 };
                 r.StructureType = "普通债券类收益互换";
-                r.ExerciseDate = QdpCalendarHelper.GetNonHolidayDefore(r.StartDate.Value.AddDays(14), GetBestCountry(r.StartDate.Value.Year));
                 tradeExtendJson.FlowBookMode = (int)FlowBookModeEnum.先进先出;
                 r.trade_extend = new trade_extend()
                 {

YLErpWeb/wwwroot/Scripts/app/swaptrade/swapTradeEdit.js

@@ -191,6 +191,13 @@ const vue = new Vue({
         $("#MainProtocolCode").val(this.trade.MetaDic["主协议编号"]);
         $("#SupProtocolCode").val(this.trade.MetaDic["补充协议编号"]);
         this.initSwapRateList();
+        // 初始化到期日期选择器下限
+        this.$nextTick(() => {
+            if (this.$refs.exerciseDatePicker) {
+                var minDate = this.trade.StartDate > this.trade.TradeDate ? this.trade.StartDate : this.trade.TradeDate;
+                this.$refs.exerciseDatePicker.refresh(minDate, null);
+            }
+        });
     },
     methods: {
         getPosiPriceFormatKey(item, field) {

YLErpWeb/wwwroot/Scripts/fast/fastVue.components.js

@@ -24,9 +24,9 @@
                         }
 
                     }).datepicker({
-                        minDate: self.mindate,
+                        minDate: self.mindate ? new Date(self.mindate) : null,
                         beforeShowDay(date) {
-                            return [(!self.maxdate || date <= new Date(self.maxdate)) && (self.noholiday || !ylotc.isHoliday(date))];
+                            return [(self.noholiday || !ylotc.isHoliday(date))];
                         },
                         changeMonth: true,
                         changeYear: true,