fix(PdfPreviewPage): 修复PDF预览页关闭时未清除刷新标记的问题

添加组件挂载时的主动刷新逻辑，避免无限刷新

@@ -12,7 +12,7 @@
 </template>
 
 <script setup>
-import { computed } from 'vue'
+import { computed, onMounted } from 'vue'
 import { useRoute, useRouter } from 'vue-router'
 import PdfViewer from '@/components/ui/PdfViewer.vue'
 
@@ -31,7 +31,13 @@ const pdfTitle = computed(() => {
   return typeof title === 'string' ? decodeURIComponent(title) : ''
 })
 
+/**
+ * 处理关闭事件
+ */
 const handleClose = () => {
+  // 清除刷新标记
+  sessionStorage.removeItem('pdf-preview-refreshed')
+  
   const returnId = route.query.returnId
   const openMaterials = route.query.openMaterials
   if (returnId) {
@@ -42,6 +48,18 @@ const handleClose = () => {
     router.replace({ path: '/study' })
   }
 }
+
+/**
+ * 组件挂载时主动刷新页面
+ */
+onMounted(() => {
+  // 检查是否已经刷新过，避免无限刷新
+  const hasRefreshed = sessionStorage.getItem('pdf-preview-refreshed')
+  if (!hasRefreshed) {
+    sessionStorage.setItem('pdf-preview-refreshed', 'true')
+    window.location.reload()
+  }
+})
 </script>
 
 <style scoped>