[BUG] `claude attach <id>` does not accept the full session id.

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?

Say, the session id of some existing session is 79db8380-c488-4143-8921-d9325e777885.

claude attach 79db8380-c488-4143-8921-d9325e777885 does not work while claude attach 79db8380 does. It's counter-intuitive.

What Should Happen?

claude attach <id> resolves the full session ID.

Error Messages/Logs

Steps to Reproduce

1. Pick any bg session and get the session id
2. Try claude attach <full session id>

Claude Model

None

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.1.146

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

iTerm2

Additional Information

_No response_