The closest i can think of is NetlifyCMS, but it's terrible because it's a bunch of JavaScript both server side and client side, and is really not intended to be selfhosted despite being open-source.

If NetlifyCMS was a robust library for abstracting over versioning system and static site generator to build WebUI/TUI/GUI clients with, that would fit what i have in mind. I don't know of any such program yet, please let me know if you find something :)