### 📦 Deployment Method

Docker

### 📌 Version

v2.12.4

### 💻 Operating System

Ubuntu

### 📌 System Version

22.04

### 🌐 Browser

Chrome

### 📌 Browser Version

Google Chrome 126.0.6478.126

### 🐛 Bug Description

I have deploied my webdav service, and can access it with curl

`➜ ~ curl -u USERNAME:PASSWD http://MY_HOSTNAME:3971/`

got html output:

```

Index of /

Index of /

• a.txt


• testfile.txt

```

but In my nextchat's config, I click "检查可用性” (check available）
it sends http req

https://MY_CHAT_HOST/api/webdav/chatgpt-next-web?endpoint=http://MY_ADV_HOST:3971

got 400 bad request

when I click sync
it sends http req
https://MY_CHAT_HOST/api/webdav/chatgpt-next-web/backup.json?endpoint=http://MY_ADV_HOST:3971
got resp
404

I have already insert my endpoint to white list using docker-compose

```
chatgpt:
image: yidadaa/chatgpt-next-web:using
container_name: chatgpt
environment:
- WHITE_WEBDEV_ENDPOINTS=http://MY_HOST:3971
restart: always
```

### 📷 Recurrence Steps

_No response_

### 🚦 Expected Behavior

_No response_

### 📝 Additional Information

_No response_

Start at the /api/webdav/chatgpt-next-web and /api/webdav/chatgpt-next-web/backup.json handlers, then compare their endpoint handling with the WHITE_WEBDEV_ENDPOINTS Docker configuration and the reported curl response. Done means the availability check and backup request work against the listed self-hosted WebDAV endpoint without returning 400 or 404.

Written by the indexing model from the issue text.