fix: 修复折叠日历组件在隐藏头部时按钮显示异常

在日历头部隐藏时，切换按钮仍会显示导致布局异常。通过添加 v-if 条件判断，仅在头部未隐藏时显示切换按钮，避免视觉错乱。

 <!--
  * @Date: 2025-01-25 15:34:17
  * @LastEditors: hookehuyr hookehuyr@gmail.com
- * @LastEditTime: 2026-01-22 20:44:20
+ * @LastEditTime: 2026-01-23 09:33:40
  * @FilePath: /mlaj/src/components/calendar/CollapsibleCalendar.vue
  * @Description: 可折叠日历组件
 -->
@@ -29,7 +29,7 @@
                 <div class="calendar-date-display" @click="expandCalendar">
                     <div class="calendar-date-main">{{ formattedCurrentDate }}</div>
                     <div class="calendar-weekday">{{ formattedWeekday }}</div>
-                    <div class="text-xs text-gray-500 mt-1 collapsible-text px-3 py-1 bg-white text-center rounded-full border border-gray-200 inline-block min-w-[5rem] max-w-[8rem]">{{ toggleButtonText }}</div>
+                    <div v-if="!isHeaderHidden" class="text-xs text-gray-500 mt-1 collapsible-text px-3 py-1 bg-white text-center rounded-full border border-gray-200 inline-block min-w-[5rem] max-w-[8rem]">{{ toggleButtonText }}</div>
                 </div>
                 <!-- <div class="calendar-action">
                     <div class="calendar-action-text">指定日期</div>