CI to check pre-commit updates from renovate

When renovate updates the pre-commit config, we should run `pre-commit run --all-files` in CI to ensure it doesn't break things.

No CI file is named; start by locating the repository's CI configuration and the Renovate settings for pre-commit updates. Add the requested all-files pre-commit check to CI, then verify that the check runs successfully against the repository contents and remains relevant after a Renovate update.

Written by the indexing model from the issue text.