CLI and mobile app keep divergent session names; they sync only at fresh-session creation

What happens

The Claude Code CLI and the Claude mobile app appear to hold separate session-name fields that are synchronised only when a session is first created. After that they diverge, and each rename path writes only one of them.

Observed behaviours, all in the same session:

• Fresh session: name matches in CLI and mobile app. Correct.
• Resumed session (claude --resume, selected by name): CLI shows the correct original name; the mobile app shows an auto-generated 3-word name it picked itself.
• /rename from the CLI: CLI name updates. Mobile title bar keeps the auto-generated 3-word name.
• /rename typed into the mobile app's prompt input: the Session renamed to: ... confirmation appears in the chat, and the new name does propagate back to the CLI, but the mobile window's title is still the old auto-generated name.
• "Rename" from the mobile app's burger menu: the new name persists in the mobile app, but never reaches the CLI.

Expected

One session name, shared. A rename from any surface updates every surface, and a resumed session keeps the name it was resumed by.

Repro

1. Create a session, note the name matches in CLI and mobile app.
2. Exit. Start a new Claude Code instance and resume that session by name.
3. Mobile app now shows an auto-generated 3-word name; CLI shows the real one.
4. /rename from the CLI. Mobile title unchanged.
5. /rename from the mobile prompt input. CLI updates, mobile title unchanged.
6. Burger menu -> Rename in the mobile app. Mobile updates, CLI unchanged.

Environment

• Platform: Linux
• Surface: Claude Code CLI + Claude mobile app
• Model: claude-opus-5[1m]