VSCode extension does not restore renamed session titles

Description

When you rename a session in the VSCode extension (via the hover action on a session in the history), the custom name is lost after restarting VSCode. The session reverts to its auto-generated title.

Steps to reproduce

1. Open Claude Code in VSCode
2. Start a conversation
3. Rename the session to a custom name
4. Close and reopen VSCode
5. Open the session history

Expected behavior

The session should retain its custom name across VSCode restarts.

Observed behavior

The session reverts to its auto-generated name.