@Simeon - recently upgraded my iPad 2 to a 2018 version 6. Signed onto it with my account and downloaded Codea. No projects other than examples etc. Used file app to look in iCloud and quite a few projects there with the little cloud and arrow hovering over them. Ran a couple, didn’t work but looked to be due to resources. Noted that they were not saved to the project list. Downloaded another, just needed a dependency on cameras set up - then worked fine. Closed the project and looked on project list - not there. Typed in a simple project and it was saved to projects and visible.
I assume this is due to edited files being stored in their default path - is that the case. It could be useful to indicate the project source on the project icon, say a cloud in the top right hand corner or similar icon. I take it we need to copy projects with the file app, and resources, to the Codea Documents (root) folder to retain them in the project file window.
Also worth considering is adding a version variable to Codea for files which could also be displayed on the project icon - in these days of multiple files stored in various locations (local/LAN/Cloud) it could be useful - I know you can add this to the file name.