ci-setup.txt
Set up CI for my project. Repo on <GitHub / GitLab>. Stack: <stack>.

Keep it minimal:
- Run on push and on pull requests.
- Install dependencies from the lockfile, exactly.
- Run <tests / type check / lint> — say which are worth having and
  which are noise for a project this size.
- Fail loudly, with output I can read without opening five sections.
- Cache dependencies so it isn't slow.

Don't add deployment yet. Then tell me roughly how long this will take
per run, and what it costs on the free tier.

Keep CI under a couple of minutes. A slow pipeline gets ignored, and an ignored pipeline is worse than none because it looks like coverage.