Sessions within a project group are not sorted by date — new sessions appear at the bottom instead of the top

Body:
When adding a new session to a project group in the session sidebar (e.g. a group named after a local project like my-project), the new session is appended to the bottom of the group instead of appearing at the top.

Expected behavior: sessions within a group should be sorted by date (most recent first), or at minimum a newly created session should always appear at the top of its group, so the latest work is immediately visible without scrolling.

Currently there appears to be no setting in settings.json or elsewhere to control this ordering — it seems to be fixed application behavior.