

The answers about using Dockerfiles are absolutely correct, but if you’re looking for a quick and simple solution that will work locally, you can always just use the “commit” docker command. This basically saves the current state of a container as a new image. You can then run new containers from that image as needed.
See https://stackoverflow.com/questions/44480740/how-to-save-a-docker-container-state
From what little I know of the way Japanese humour works, there’s a decent chance this is all just a bit. There was a guy in Japan who married a different kind of virtual girlfriend not that long before LLMs hit the mainstream, and I heard from a few different Japanese people that he was almost certainly doing it as a joke. Apparently Japanese humour is very, very deadpan and they love seeing people really commit to the bit.