I was just about to make a new thread asking for the same feature. The new features allowing the grouping by project is very welcome. I have been organizing my various projects using this method. One trick for me was to create a workpiece that contains just text, which is not intended to be actually carved, but hold notes to myself about the project.
Most of my work involves using the same design over and over, so the ability to mark a given workpiece as read only would be most welcome. The read-only could be at the project level instead, if that was easier. Another alternative would be to add the option to open the project in read-only mode, or once open to click a checkbox to indicate changes would not be allowed.
In all cases, the read-only status needs to be able to be changeable.