[VSCode Extension] Custom session names revert after conversation continues

Description

In the VSCode extension, manually renaming a session via the pencil (✏️) icon does not persist. After the conversation continues, the name reverts to the auto-generated summary.

Steps to Reproduce

1. Open session list in VSCode extension sidebar
2. Click the pencil icon on any session
3. Enter a custom name and confirm
4. Continue the conversation
5. Observe: the custom name is overwritten by an auto-generated summary

Expected Behavior

Custom session names should persist and not be overridden by auto-generated summaries.

Actual Behavior

The custom name reverts to an auto-generated conversation summary.

Additional Context

• The /rename slash command is not available in the VSCode extension environment
• CLI version has /rename command which may work correctly
• Environment: VSCode Extension