GitHub Actions guides

One guide per check in our CI study. Each fix is a few lines of YAML.

• How to cache dependencies in GitHub Actions (npm, pnpm, yarn)

  Stop re-downloading node_modules on every run: the one-line setup-node cache, pnpm and yarn setups, actions/cache for everything else, and when not to cache.

• Cancel outdated GitHub Actions runs on pull requests with concurrency

  Every push to a PR starts a new run while the old one keeps going. A 3-line concurrency group cancels it, without cancelling deploys on main.

• GitHub Actions timeout-minutes: the 6-hour default and how to set it

  A hung job runs for 360 minutes by default. How timeout-minutes works for jobs and steps, how to pick a value, and what usually hangs.