Okay, so apparently I have to go to Settings → Rules, create one for the main branch so that the default ruleset no longer applies, and then untick "Automatically request Copilot code review – Request Copilot code review for new pull requests automatically if the author has access to Copilot code review and their premium requests quota has not reached the limit" way at the bottom.

Great.

I think we'll be moving to codeberg soon.