- Change design a bit so that the separation between projects is clearer
- Add ability to cmd-click to focus most recent workspace
- Make hover and collapse/expand interactions unconditional, enabled by
adding a "No threads yet" empty state
- Improved keyboard nav by making cmd-n create a new thread in the
currently focused group


https://github.com/user-attachments/assets/e9cde153-d3f1-4945-9e45-db1597637a44

Release Notes:

- Agent: Improved the threads sidebar header by making the separation
between projects more distinct.