snapshot of the essepunto spec, otherwise working only intermittently

@elf-pavlik help? I can't remember how to test this in gitbook (works directly from my local drive) - but I think there is a way to do that. I'm thinking we'll need to take snapshots by just saving in the browser when we add things. And see if it is stays up more than it is down.

Ref. https://github.com/valueflows/valueflows/issues/493 which I will close and just leave this open.