enabling self play

hi,
i tried out this project and it is one of the few that actually works off the shelf, thank you for your work.
Is there a way to enable self play when training an agent? My usecase is to use DreamerV3 as a alternative to algorithms such as muzero to train agents for boardgames.
I have looked around the repo but this feature does not seem trivially available out of the box.

Start by locating the DreamerV3 training entry point and the environment setup used during training, then determine how self-play would fit the existing agent workflow. Done would require a clearly defined self-play behavior and validation that it supports the requested board-game training use case.

Written by the indexing model from the issue text.