🐛 customTitle not restored when resuming session via --resume <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?

When a session is renamed via /rename, the customTitle is correctly persisted to both the JSONL file (as a custom-title entry) and to sessions-index.json (as a customTitle field).

However, when resuming that session via claude --resume <session-id>, the custom title is not restored — the blue label in the input area does not appear.

What Should Happen?

Expected: The blue "my-session" label appears in the input area, matching the state before exit
Actual: No label appears — the session resumes without its custom title

Steps to Reproduce

1. Start a new Claude Code session
2. Run /rename my-session
3. Verify the blue "my-session" label appears in the bottom-right of the input area
4. Exit the session
5. Resume with claude --resume <session-id>

The customTitle is correctly stored in two places:

sessions-index.json:
{
  "sessionId": "002eed07-...",
  "customTitle": "my-session",
  ...
}

Session JSONL (inline entry):
{"type": "custom-title", "customTitle": "my-session", "sessionId": "..."}

The data survives the round-trip — it's just not being read back on resume.

Related

This is closely related to #24502, which reports customTitle being ignored in the /resume picker after /clear. Both bugs stem from customTitle not being properly read back from
persisted state. This bug is about the in-session display; #24502 is about the picker display.

Also related to #23610

Additional Information

• Is this a regression?: I don't know
• Code Version: 2.1.38
• Platform: Anthropic API
• Operating System: macOS
• Terminal/Shell: Terminal.app (macOS)