Allow use of worktrees created outside codex app

What version of the Codex App are you using (From “About Codex” dialog)?

Version 26.224.1209 (697)

What subscription do you have?

ChatGPT Plus

What platform is your computer?

Darwin 24.6.0 arm64 arm

What issue are you seeing?

If I create a worktree using a standard git command and then try to open a Codex session inside it, the worktree's branch name appears in the bottom-right dropdown menu. However, when I select that branch to start working, I get an error message that says:

Failed to switch branch fatal: branch name is already used by worktree at .....

What steps can reproduce the bug?

• create a local worktree manually (not through codex)
• try to use codex against that worktree by selecting the branch name
• see an error stating:

<img width="1214" height="232" alt="Image" src="https://github.com/user-attachments/assets/83f62621-70c7-439d-9453-a22e6c3d58cf" />

What is the expected behavior?

Should be able to point the codex app to use a worktree created outside of codex

Additional information

_No response_