[BUG] Session name set via /rename does not persist after restart

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?

Bug

Session names set with /rename are displayed in the bottom-right status bar during the active session, but after restarting Claude Code,
the custom name is not shown in the /resume picker.

What Should Happen?

Expected behavior

The /resume picker should display the custom name set via /rename.

Observed behavior

/resume always shows the firstPrompt or auto-generated summary, ignoring the name set by /rename.

Error Messages/Logs

Steps to Reproduce

1. Start a new session in cashare-fresh project
2. Rename the session: /rename https://cashare-test.atlassian.net/browse/CAS-2011
3. Observe the name appears in the bottom-right status bar (blue text)
4. Exit the session
5. Run /resume
6. The session shows its original first prompt, not the renamed value CAS-2011

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.81

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

<img width="2451" height="1600" alt="Image" src="https://github.com/user-attachments/assets/9249c043-8ed3-4260-ab65-e17aa5f4b335" />