Addon A11y: Fix setup as part of storybook create

[yannbf]

Closes #31402

What I did

This PR fixed the postinstall execute, using execa in a compatible way

Checklist for Contributors

Testing

The changes in this PR are covered in the following automated tests:

• stories
• unit tests
• integration tests
• end-to-end tests

Manual testing

This section is mandatory for all contributions. If you believe no manual test is necessary, please state so explicitly. Thanks!

Documentation

• Add or update documentation reflecting your changes
• If you are deprecating/removing a feature, make sure to update
  MIGRATION.MD

Checklist for Maintainers

• When this PR is ready for testing, make sure to add ci:normal, ci:merged or ci:daily GH label to it to run a specific set of sandboxes. The particular set of sandboxes can be found in code/lib/cli-storybook/src/sandbox-templates.ts

• Make sure this PR contains one of the labels below:

  Available labels

  • bug: Internal changes that fixes incorrect behavior.
  • maintenance: User-facing maintenance tasks.
  • dependencies: Upgrading (sometimes downgrading) dependencies.
  • build: Internal-facing build tooling & test updates. Will not show up in release changelog.
  • cleanup: Minor cleanup style change. Will not show up in release changelog.
  • documentation: Documentation only changes. Will not show up in release changelog.
  • feature request: Introducing a new feature.
  • BREAKING CHANGE: Changes that break compatibility in some way with current major version.
  • other: Changes that don't fit in the above categories.

🦋 Canary release

This pull request has been released as version 0.0.0-pr-31403-sha-04221415. Try it out in a new sandbox by running npx [email protected] sandbox or in an existing project with npx [email protected] upgrade.

More information

Published version	0.0.0-pr-31403-sha-04221415
Triggered by	@yannbf
Repository	storybookjs/storybook
Branch	yann/fix-a11y-postinstall
Commit	04221415
Datetime	Wed May 7 11:25:25 UTC 2025 (1746617125)
Workflow run	14882163310

To request a new release of this pull request, mention the @storybookjs/core team.

core team members can create a new canary release here or locally with gh workflow run --repo storybookjs/storybook canary-release-pr.yml --field pr=31403

Greptile Summary

Updates the postinstall script for the Vitest addon to improve accessibility addon setup and error handling during Storybook initialization.

• Modified code/addons/vitest/src/postinstall.ts to reorder a11y addon setup after Vitest configuration
• Improved error handling by displaying actual error messages during a11y setup failures
• Optimized command structure by removing redundant 'storybook' from command array
• Added conditional config-dir flag only for non-default Storybook directories

[nx-cloud]

View your CI Pipeline Execution ↗ for commit 0422141.

Command	Status	Duration	Result
nx run-many -t check -c production --parallel=7	✅ Succeeded	7s	View ↗
nx run-many -t build -c production --parallel=3	✅ Succeeded	19s	View ↗

---

☁️ Nx Cloud last updated this comment at 2025-05-07 11:32:56 UTC

[storybook-bot]

Failed to publish canary version of this pull request, triggered by @yannbf. See the failed workflow run at: https://github.com/storybookjs/storybook/actions/runs/14880746512

[greptile-apps]

LGTM

_{1 file(s) reviewed, no comment(s)
Edit PR Review Bot Settings | Greptile}