Time to refresh the CI setup

Time to refresh the CI setup: a task in MiMo-V2.6-RL-harbor-code: MiMo-V2.6-RL Code (Harbor) (Harbor dataset). The .github/workflows/pre-commit.yml workflow and the pre-commit config are starting to feel out of date and the test suite is needlessly slow / network-dependent. Filing this so we don't…