🐛[BUG] mega sync与浏览器插件/网页版无法登录

### 🐛 描述(Description)
桌面客户端无法登录，网页版/插件有时无法登录，在mega sync中设置代理（无代理或自动侦测）可成功通过网络检查
桌面客户端换用其他工具成功登录后切换回steam++反代，代理设置检查通过，但仍然无法传输文件
网页版/浏览器插件换用其他工具登陆成功后切换回steam++反代，成功上传文件

### 📷 复现步骤(Steps to Reproduce)

1. 开启mega加速（hosts模式）
2. 打开mega sync
3. 卡在正在登陆环节

### 📄 [异常/日志]信息([Exception/Log] Information)

### 🚑 基本信息(Basic Information)

- 程序版本(Program Version): 2.7.2 FDE
- 系统版本号(OS Version): Windows 22621.232
- 是否为应用商店版本(Whether it is a Store version): 否

### 🖼 截图(Screenshots)


Start by reproducing issue #1676 with hosts-mode acceleration and Mega Sync on Windows 22621.232, then compare login and file-transfer behavior with the proxy set to no proxy or automatic detection. Check the browser/plugin behavior separately and gather the missing logs; done means the affected Mega workflows work reliably through Steam++ without switching to another tool.

Written by the indexing model from the issue text.