[Bug] Unable to log in on Desktop App (Linux/Win/Mobile) via MonkeyCode Cloud / GitHub OAuth despite valid web credentials

Describe the Bug
Accounts registered/authenticated through the web application (monkeycode-ai.net) via Google/GitHub OAuth fail to log in to the native Desktop Application (MonkeyCode_latest_amd64.AppImage on Linux, as well as Windows and Mobile clients).

Attempting to sign in under Settings → Account → MonkeyCode Cloud using the account email and a password created via "Set password" in the web panel continuously returns 登录失败 (Login Failed).

Additionally, because authentication fails, the desktop application remains unusable in offline or local-first modes without active login.

Steps to Reproduce
Create/login to an account on monkeycode-ai.net using OAuth (Google / GitHub).

Go to Account Settings on the web dashboard and set a password via the Set password prompt.

Verify that the login works on standard web browsers (it succeeds).

Launch the desktop client (MonkeyCode_latest_amd64.AppImage on Linux or Windows binary).

Open Settings → Account.

Scroll to MonkeyCode Cloud and enter the valid Email + Password.

Click Sign in.

Expected Behavior
The desktop application should authenticate the user using the credentials created on monkeycode-ai.net or support direct web/GitHub OAuth callback.

Alternatively, the application should allow local-first operation without requiring mandatory cloud authentication.

Actual Behavior
The UI displays a red error message: 登录失败 (Login Failed).

No alternative login endpoint or OAuth redirect prompt is provided for global users without a WeChat or mainland China SMS number.

Environment Details
OS: Ubuntu (Linux x86_64 AppImage) / Windows

App Version: MonkeyCode_latest_amd64.AppImage

Account Auth Type: Web OAuth (Google / GitHub) + Set Password

Repository: chaitin/MonkeyCode

Additional Context / Logs
Terminal execution logs on Linux:

[desktop] main 进入
[desktop] 登录 shell 环境已解析(74 项)
[desktop] ohmyagent 就绪 version=f2e9212 caps=18
[desktop] ohmyagent 引擎就绪
[desktop] 桌宠已创建: visible=Ok(true) pos=Ok(PhysicalPosition { x: 1578, y: 857 }) size=Ok(PhysicalSize { width: 116, height: 120 })

Start at Settings → Account → MonkeyCode Cloud and compare the native sign-in flow with the web dashboard's Set password flow for Google/GitHub accounts. Reproduce the failure on the Ubuntu AppImage or Windows client, then verify that valid web credentials or a supported OAuth callback authenticate successfully, with local-first access available if cloud login is not required.