[Bug] Webdav 同步失败

**Describe the bug**
利用Koofr提供的Webdav服务做同步。提示成功，但是登录到Koofr没有新增任何文件。
前几个版本是正常的，最后同步成功的时间是13天前。

**To Reproduce**
Steps to reproduce the behavior:
1. 点击 设置
2. 点击 同步
3. 提示 同步成功

**Expected behavior**
期望正常的同步成功备份文件

**Screenshots**

**Deployment**
- Vercel

**Desktop (please complete the following information):**
- OS: windows 11
- Browser: chrome
- Version: 2.9.13

Start with the Settings > Sync flow and the WebDAV integration used for Koofr, then reproduce the reported successful sync on Windows 11 with Chrome and version 2.9.13. Check whether a backup file appears in Koofr despite the success message; the work is done when the sync result accurately reflects whether the file was uploaded.

Written by the indexing model from the issue text.