feat(StudyDetailPage): 添加复制文件地址功能按钮

在文件列表项中添加复制地址按钮，方便用户快速复制文件链接
实现现代浏览器和旧浏览器的兼容方案

@@ -534,11 +534,20 @@
                                 </div>
                                 </div>
                                 <div class="flex-1 min-w-0">
                                 <div class="flex-1 min-w-0">
                                     <h3 class="text-base font-semibold text-gray-900 mb-2 line-clamp-2">{{ file.title || file.name }}</h3>
                                     <h3 class="text-base font-semibold text-gray-900 mb-2 line-clamp-2">{{ file.title || file.name }}</h3>
-                                    <div class="flex items-center gap-4 text-sm text-gray-600">
+                                    <div class="flex items-center justify-between gap-4 text-sm text-gray-600">
                                         <div class="flex items-center gap-1">
                                         <div class="flex items-center gap-1">
                                             <van-icon name="label-o" size="12" style="margin-right: 0.25rem;"/>
                                             <van-icon name="label-o" size="12" style="margin-right: 0.25rem;"/>
                                             <span>{{ getFileType(file.title || file.name) }}</span>
                                             <span>{{ getFileType(file.title || file.name) }}</span>
                                         </div>
                                         </div>
+                                        <!-- 复制地址按钮 -->
+                                        <button
+                                            @click="copyFileUrl(file.url)"
+                                            class="flex items-center gap-1 px-2 py-1 text-xs text-gray-500 hover:text-gray-700 hover:bg-gray-50 rounded transition-colors"
+                                            title="复制文件地址"
+                                        >
+                                            <van-icon name="link" size="12" />
+                                            <span>复制地址</span>
+                                        </button>
                                     </div>
                                     </div>
                                 </div>
                                 </div>
                             </div>
                             </div>
@@ -1252,7 +1261,44 @@ const downloadFailInfo = ref({
 const showMaterialsPopup = ref(false);
 const showMaterialsPopup = ref(false);
 
 
 /**
 /**
- * 复制文件URL到剪贴板
+ * 复制文件地址到剪贴板
+ * @param {string} url - 要复制的文件地址
+ */
+const copyFileUrl = async (url) => {
+    try {
+        if (navigator.clipboard && window.isSecureContext) {
+            // 现代浏览器支持的方式
+            await navigator.clipboard.writeText(url);
+            showToast('文件地址已复制到剪贴板');
+        } else {
+            // 兼容旧浏览器的方式
+            const textArea = document.createElement('textarea');
+            textArea.value = url;
+            textArea.style.position = 'fixed';
+            textArea.style.left = '-999999px';
+            textArea.style.top = '-999999px';
+            document.body.appendChild(textArea);
+            textArea.focus();
+            textArea.select();
+
+            try {
+                document.execCommand('copy');
+                showToast('文件地址已复制到剪贴板');
+            } catch (err) {
+                console.error('复制失败:', err);
+                showToast('复制失败，请手动复制地址');
+            } finally {
+                document.body.removeChild(textArea);
+            }
+        }
+    } catch (err) {
+        console.error('复制到剪贴板失败:', err);
+        showToast('复制失败，请手动复制地址');
+    }
+};
+
+/**
+ * 复制到剪贴板
  * @param {string} url - 要复制的URL
  * @param {string} url - 要复制的URL
  */
  */
 const copyToClipboard = async (url) => {
 const copyToClipboard = async (url) => {