Perhaps it's too obvious but ... just running the publish process locally, instead of from CI, would help. Especially if you publish from a dedicated user on a Mac where the system keychain is pretty secure.
This problem is solved by not having a token. Github and PyPI both support OIDC based workflows. Grant only the publish job access to OIDC endpoint, then the Trivy job has nothing it can steal.
I'm not sure how. Their local system seems just as likely to get compromised through a `pip install` or whatever else.
In CI they could easily have moved `trivy` to its own dedicated worker that had no access to the PYPI secret, which should be isolated to the publish command and only the publish command.