Custom groups/folders for session sidebar (recent items list)

Feature request

The session sidebar (recent items list) currently only supports chronological ordering. There's no way to create custom groups/folders to organize sessions by topic or project.

Motivation

I work across many unrelated topics/projects in the same account, and the flat recency-sorted list makes it hard to find related past sessions once several new ones push older ones down.

Proposed solution

Allow users to create custom groups/folders in the sidebar and manually assign sessions to them, instead of (or in addition to) the automatic recency ordering.