[Request] Disable continuous terminal rewriting in CI

[JoshuaKGoldberg]

Is your feature request related to a problem? Please describe.

Spinning out from JoshuaKGoldberg/create-typescript-app#859: when running Clack's spinners in a project in CI (e.g. GitHub Actions), you get a ton of CI logs:

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◇  ✅ Passed migrating repository structure.
[25](https://github.com/JoshuaKGoldberg/create-typescript-app/actions/runs/6264408991/job/17011040698?pr=858#step:5:26)l│
◒  Cleaning up files◐  Cleaning up files◓  Cleaning up files◑  Cleaning up files◒  Cleaning up files◐  Cleaning up files◓  Cleaning up files◑  Cleaning up files◒  Cleaning up files.◐  Cleaning up files.◓  Cleaning up files.◑  Cleaning up files.◒  Cleaning up files.◐  Cleaning up files.◓  Cleaning up files.◑  Cleaning up files.◒  Cleaning up files..◐  Cleaning up files..◓  Cleaning up files..◑  Cleaning up files..◒  Cleaning up files..◐  Cleaning up files..◓  Cleaning up files..◑  Cleaning up files..◒  Cleaning up files...◐  Cleaning up files...◓  Cleaning up files...◑  Cleaning up files...◒  Cleaning up files...◐  Cleaning up files...◓  Cleaning up files...◑  Cleaning up files...◒  Cleaning up files...◐  Cleaning up files◓  Cleaning up files◑  Cleaning up files◒  Cleaning up files◐  Cleaning up files◓  Cleaning up files◑  Cleaning up files◒  Cleaning up files◐  Cleaning up files.◓  Cleaning up files.◑  Cleaning up files.◒  Cleaning up files.◐  Cleaning up files.◓  Cleaning up files.◑  Cleaning up files.◒  Cleaning up files.◐  Cleaning up files..◓  Cleaning up files..◑  Cleaning up files..◒  Cleaning up files..◐  Cleaning up files..◓  Cleaning up files..◑  Cleaning up files..◒  Cleaning up files..◐  Cleaning up files...◓  Cleaning up files...◑  Cleaning up files...◒  Cleaning up files...◐  Cleaning up files...◓  Cleaning up files...◑  Cleaning up files...◒  Cleaning up files...◐  Cleaning up files...◓  Cleaning up files◑  Cleaning up files◒  Cleaning up files◐  Cleaning up files◓  Cleaning up files◑  Cleaning up files◒  Cleaning up files◐  Cleaning up files◓  Cleaning up files.◑  Cleaning up files.◒  Cleaning up files.◐  Cleaning up files.◓  Cleaning up files.◑  Cleaning up files.◒  Cleaning up files.◐  Cleaning up files.◓  Cleaning up files..◑  Cleaning up files..◒  Cleaning up files..◐  Cleaning up files..◓  Cleaning up files..◑  Cleaning up files..◒  Cleaning up files..◐  Cleaning up files..◓  Cleaning up files...◑  Cleaning up files...◒  Cleaning up files...◐  Cleaning up files...◓

Describe the solution you'd like

Could we an option to disable terminal animations, so each line is only logged once? Ideally that option would default to auto-detecting whether the environment is a CI one.

Describe alternatives you've considered

User-land code could avoid spinners in CI by doing the detection themselves. That's a lot of work for each consuming project though.

Additional context

I'd be happy to implement this - though might not have time soon.

[orochaa]

GitHub Actions sets common environment variables that we can use to determine if the code is running in their environment. We can do something like process.env.GITHUB_ACTIONS === 'true' to auto detect it.

[antony]

We can do something like process.env.GITHUB_ACTIONS === 'true' to auto detect it.

You should probably look for the more universal process.env.CI instead, which is what I use currently to basically disable clack for this reason.