Does github not have rulesets for who can even try to do a PR? I would lockdown my repositories if I didn't want any PR slop.
Most open source projects want outside contributions... as long as they are decent quality. The problem is how do you block the AI slop spam without also blocking high quality contributions.
They do, that's a relatively recent feature: https://docs.github.com/en/repositories/managing-your-reposi...