[BUG] Chat/Cowork/Code mode tabs missing from top of desktop app

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

The top-level tabs that used to let me switch between Chat, Cowork, and Code modes have disappeared from the desktop app UI. I couldn't find any changelog entry documenting this change, and the current docs (desktop.md) still describe these tabs as present.

What Should Happen?

The Chat/Cowork/Code tabs should be visible at the top and clickable to switch modes.

Error Messages/Logs

Steps to Reproduce

1. Open the Claude Code desktop app.
2. Look at the top of the window where the Chat / Cowork / Code mode tabs used to be.
3. Observe that the tabs are no longer there, with no documented way to switch modes.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.235 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

_No response_