Each night, move Cargo.lock to the current main of each internal
library with `cargo update -p` and run the Linux test suite on it.
A passing update opens or updates one pull request from
`bot/internal-deps` with the new lock; a failure opens or comments on
one tracking issue labeled `internal-deps`, and the next passing run
closes it.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>