## Context

- Improve how we detect when the sidebar should render the empty state.
It was previously wrong using `content.entries.is_empty`, which would
also happen if there are no search matches.
- Improved archive view keyboard nav and design. Not using the ListItem
here anymore so as to avoid confusing hover and active states.
- Move archive and open folder buttons to the bottom of the sidebar.
- Add a new flavor of the recent projects for the sidebar that only
serves as a way to _add_ projects.
- Add the ability to add (and remove) folders to a given project group
in the sidebar through a dropdown menu
--- 
- [x] I've reviewed my own diff for quality, security, and reliability
- [x] Unsafe blocks (if any) have justifying comments
- [x] The content is consistent with the [UI/UX
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
- [x] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable

Release Notes:

- N/A