We have a few projects which need to remain accessible to searching / viewing, but we no longer want to allow edits or submissions to the project. I thought I could just make the entire project inactive, but can't find a way to accomplish this.
Just 'delete' the project. After Admin → Projects → Edit → Delete, I get:
There are open cases in this project.
These cases will not be deleted but
you will no longer be able to create
new cases in this project. Click here
to see a list of the cases currently
in this project.
Do you want to delete the 'xyz'
So it's a bit disguised but does exactly what you want.