feat(prompts): support maxItems in groupMultiselect

[bluwy]

What does this PR do?

If groupMultiselect have many items, it interferes with the rendering instead of scrolling itself. This PR implements the scrolling behaviour similar to multiselect using limitOptions.

Also, due to refactoring for limitOptions, if withGuide: false, the multiselect will no longer have an indent, which matches the styling of multiselect and other prompts.

Closes #526

Demo:

Screen.Recording.2026-05-07.at.8.09.23.PM.mov

Additional notes

1. Much of the code and tests are referenced from multiselect
2. limitOptions does not seem to handle new lines within options well, which could happen when groupPadding > 0 is set (which prepends new lines before group options). It assumes every option takes up one line when calculating the truncation. I did not fix this in the PR as I feel it's a separate issue.
3. I thought about making the group option sticky, but I feel the scrolling could be a bit unpredictable and complex to work out.

Type of change

• Bug fix
• Feature
• Refactor (no behavior change)
• Documentation
• Performance improvement
• Tests
• Chore (dependencies, CI, tooling)

Checklist

• pnpm test passes (or targeted tests for my change)
• pnpm format has been run
• I have added/updated tests for my changes (if applicable)
• I have added a changeset

AI-generated code disclosure

• This PR includes AI-generated code

[changeset-bot]

🦋 Changeset detected

Latest commit: 70ae450

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@clack/prompts	Minor

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[pkg-pr-new]

• @example/basic

• @example/changesets

  npm i https://pkg.pr.new/@clack/core@528
  

  npm i https://pkg.pr.new/@clack/prompts@528
  

commit: 70ae450

[43081j]

i will fix the problem with wrapping. it isn't only in limitOptions, its mostly in group multi-select itself.

gnarly stuff but i'll sort it in a follow up