refactor(PdfViewer): 优化PDF查看器关闭逻辑和资源清理

添加PDF组件引用并实现销毁方法
延迟清理状态确保组件完成内部清理
新增onClose和onDestroy事件通知父组件

@@ -11,14 +11,31 @@
         <div class="pdf-viewer-container">
             <!-- PDF内容区域 -->
             <div class="pdf-content" :class="{ 'pdf-no-select': preventSave }">
-                <PDF v-if="url && show && !loadingError" :src="url" :showProgress="true" :progressColor="'#1989fa'"
-                    :showPageTooltip="true" :showBackToTopBtn="true" :scrollThreshold="300"
+                <PDF v-if="url && show && !loadingError" 
+                    ref="pdfRef"
+                    :src="url" 
+                    :showProgress="true" 
+                    :progressColor="'#1989fa'"
+                    :showPageTooltip="true" 
+                    :showBackToTopBtn="true" 
+                    :scrollThreshold="300"
                     :pdfWidth="`${Math.round(100 * zoomLevel)}%`"
-                    :rowGap="8" :page="1" :cMapUrl="'https://unpkg.com/pdfjs-dist@3.7.107/cmaps/'"
-                    :withCredentials="false" :useSystemFonts="true" :stopAtErrors="false" :disableFontFace="false"
-                    :disableRange="false" :disableStream="false" :disableAutoFetch="false" @onProgress="handleProgress"
-                    @onComplete="handleComplete" @onScroll="handleScroll" @onPageChange="handlePageChange"
-                    @onPdfInit="handlePdfInit" @onError="handlePdfError" />
+                    :rowGap="8" 
+                    :page="1" 
+                    :cMapUrl="'https://unpkg.com/pdfjs-dist@3.7.107/cmaps/'"
+                    :withCredentials="false" 
+                    :useSystemFonts="true" 
+                    :stopAtErrors="false" 
+                    :disableFontFace="false"
+                    :disableRange="false" 
+                    :disableStream="false" 
+                    :disableAutoFetch="false" 
+                    @onProgress="handleProgress"
+                    @onComplete="handleComplete" 
+                    @onScroll="handleScroll" 
+                    @onPageChange="handlePageChange"
+                    @onPdfInit="handlePdfInit" 
+                    @onError="handlePdfError" />
 
                 <!-- 错误状态显示 -->
                 <div v-if="loadingError" class="error-container">
@@ -34,7 +51,7 @@
             </div>
 
             <!-- 关闭按钮 -->
-            <van-button class="close-btn" type="default" icon="cross" round @click="emit('update:show', false)" />
+            <van-button class="close-btn" type="default" icon="cross" round @click="handleClose" />
 
             <!-- 缩放控制按钮 -->
             <div v-if="!loading && !loadingError" class="zoom-controls">
@@ -70,7 +87,7 @@
 </template>
 
 <script setup>
-import { ref, watch, nextTick } from 'vue';
+import { ref, watch, nextTick, onUnmounted } from 'vue';
 import PDF from "pdf-vue3";
 
 /**
@@ -102,7 +119,7 @@ const props = defineProps({
 /**
  * 事件定义
  */
-const emit = defineEmits(['update:show', 'onLoad', 'onProgress', 'onComplete']);
+const emit = defineEmits(['update:show', 'onLoad', 'onProgress', 'onComplete', 'onClose', 'onDestroy']);
 
 // 响应式数据
 const loading = ref(true);
@@ -111,6 +128,7 @@ const loadingError = ref(false);
 const errorMessage = ref('');
 const zoomLevel = ref(1); // 缩放级别，1为100%
 const scrollPosition = ref({ x: 0, y: 0 }); // 记录滚动位置
+const pdfRef = ref(null); // PDF组件引用
 
 // 超时处理相关
 const loadingTimeout = ref(30000); // 超时时间，默认30秒
@@ -131,13 +149,21 @@ watch(() => props.show, (newVal) => {
         errorMessage.value = '';
         zoomLevel.value = 1; // 重置缩放级别
     } else if (!newVal) {
-        // 弹窗关闭时重置状态
+        // 弹窗关闭时重置状态并清理资源
         clearAllTimers(); // 清除计时器
-        loading.value = true;
+        
+        // 延迟清理，确保PDF组件有时间完成内部清理
+        setTimeout(() => {
+            loading.value = false;
             loadingError.value = false;
             loadingProgress.value = 0;
             errorMessage.value = '';
             zoomLevel.value = 1; // 重置缩放级别
+            scrollPosition.value = { x: 0, y: 0 }; // 重置滚动位置
+            
+            // 触发关闭销毁事件，通知父组件清理引用
+            emit('onClose');
+        }, 100); // 100ms延迟，给PDF组件时间清理
     }
 });
 
@@ -302,6 +328,28 @@ const retryLoad = () => {
 };
 
 /**
+ * 处理关闭弹窗
+ */
+const handleClose = () => {
+    // 先清理所有计时器
+    clearAllTimers();
+    
+    // 如果PDF组件存在，尝试清理其内部状态
+    if (pdfRef.value && typeof pdfRef.value.destroy === 'function') {
+        try {
+            pdfRef.value.destroy();
+        } catch (error) {
+            console.warn('PDF组件销毁时出现警告:', error);
+        }
+    }
+    
+    // 使用nextTick确保在DOM更新前完成清理
+    nextTick(() => {
+        emit('update:show', false);
+    });
+};
+
+/**
  * 放大PDF
  */
 const zoomIn = () => {