🐛 修复特殊字符文件名的处理问题

- 添加decodeHtmlEntities函数解码HTML实体
- 在rename/mkdir/folder-info/delete接口中解码文件名和路径
- 删除操作支持多候选路径，处理二次编码情况
- 移除sanitizeInput中对反引号的转义

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

backend/server.js

@@ -206,8 +206,7 @@ function sanitizeInput(str) {
         '<': '&lt;',
         '>': '&gt;',
         '"': '&quot;',
-        "'": '&#x27;',
+        "'": '&#x27;'
-        '`': '&#x60;'
       };
       return map[char];
     });
@@ -221,6 +220,46 @@ function sanitizeInput(str) {
   return sanitized;
 }
 
+// 将 HTML 实体解码为原始字符（用于文件名/路径字段）
+function decodeHtmlEntities(str) {
+  if (typeof str !== 'string') return str;
+
+  // 支持常见实体和数字实体（含多次嵌套，如 &amp;#x60;）
+  const entityMap = {
+    amp: '&',
+    lt: '<',
+    gt: '>',
+    quot: '"',
+    apos: "'",
+    '#x27': "'",
+    '#x2F': '/',
+    '#x60': '`'
+  };
+
+  const decodeOnce = (input) =>
+    input.replace(/&(#x[0-9a-fA-F]+|#\d+|[a-zA-Z]+);/g, (match, code) => {
+      if (code[0] === '#') {
+        const isHex = code[1]?.toLowerCase() === 'x';
+        const num = isHex ? parseInt(code.slice(2), 16) : parseInt(code.slice(1), 10);
+        if (!Number.isNaN(num)) {
+          return String.fromCharCode(num);
+        }
+        return match;
+      }
+      const mapped = entityMap[code];
+      return mapped !== undefined ? mapped : match;
+    });
+
+  let output = str;
+  let decoded = decodeOnce(output);
+  // 处理嵌套实体（如 &amp;#x60;），直到稳定
+  while (decoded !== output) {
+    output = decoded;
+    decoded = decodeOnce(output);
+  }
+  return output;
+}
+
 // HTML转义（用于模板输出）
 function escapeHtml(str) {
   if (typeof str !== 'string') return str;
@@ -2275,7 +2314,9 @@ app.get('/api/files', authMiddleware, async (req, res) => {
 
 // 重命名文件
 app.post('/api/files/rename', authMiddleware, async (req, res) => {
-  const { oldName, newName, path } = req.body;
+  const oldName = decodeHtmlEntities(req.body.oldName);
+  const newName = decodeHtmlEntities(req.body.newName);
+  const path = decodeHtmlEntities(req.body.path) || '/';
   let storage;
 
   if (!oldName || !newName) {
@@ -2313,7 +2354,8 @@ app.post('/api/files/rename', authMiddleware, async (req, res) => {
 
 // 创建文件夹
 app.post('/api/files/mkdir', authMiddleware, async (req, res) => {
-  const { path, folderName } = req.body;
+  const path = decodeHtmlEntities(req.body.path) || '/';
+  const folderName = decodeHtmlEntities(req.body.folderName);
   let storage;
 
   // 参数验证
@@ -2380,7 +2422,8 @@ app.post('/api/files/mkdir', authMiddleware, async (req, res) => {
 
 // 获取文件夹详情(大小统计)
 app.post('/api/files/folder-info', authMiddleware, async (req, res) => {
-  const { path: dirPath, folderName } = req.body;
+  const dirPath = decodeHtmlEntities(req.body.path) || '/';
+  const folderName = decodeHtmlEntities(req.body.folderName);
   let storage;
 
   if (!folderName) {
@@ -2475,7 +2518,10 @@ app.post('/api/files/folder-info', authMiddleware, async (req, res) => {
 
 // 删除文件
 app.post('/api/files/delete', authMiddleware, async (req, res) => {
-  const { fileName, path } = req.body;
+  const rawFileName = req.body.fileName;
+  const rawPath = req.body.path;
+  const fileName = decodeHtmlEntities(rawFileName);
+  const path = decodeHtmlEntities(rawPath) || '/';
   let storage;
 
   if (!fileName) {
@@ -2491,9 +2537,41 @@ app.post('/api/files/delete', authMiddleware, async (req, res) => {
     const storageInterface = new StorageInterface(req.user);
     storage = await storageInterface.connect();
 
-    const filePath = path === '/' ? `/${fileName}` : `${path}/${fileName}`;
+    const tried = new Set();
+    const candidates = [fileName];
 
-    await storage.delete(filePath);
+    // 兼容被二次编码的实体（如 &amp;#x60; -> &#x60;）
+    if (typeof rawFileName === 'string') {
+      const entityName = rawFileName.replace(/&amp;/g, '&');
+      if (entityName && !candidates.includes(entityName)) {
+        candidates.push(entityName);
+      }
+      if (rawFileName && !candidates.includes(rawFileName)) {
+        candidates.push(rawFileName);
+      }
+    }
+
+    const pathsToDelete = candidates.map(name => (path === '/' ? `/${name}` : `${path}/${name}`));
+
+    try {
+      for (const targetPath of pathsToDelete) {
+        if (tried.has(targetPath)) continue;
+        tried.add(targetPath);
+        try {
+          await storage.delete(targetPath);
+          break;
+        } catch (err) {
+          if (err.code === 'ENOENT') {
+            // 尝试下一个候选路径
+            if (targetPath === pathsToDelete[pathsToDelete.length - 1]) throw err;
+          } else {
+            throw err;
+          }
+        }
+      }
+    } catch (err) {
+      throw err;
+    }
 
     res.json({
       success: true,