don't use path.join for module specifiers

[delagen]

Closes #32872

What I did

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 PR does not have a canary release associated. You can request a canary release of this pull request by mentioning the @storybookjs/core team here.

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

[nx-cloud]

View your CI Pipeline Execution ↗ for commit 523beab

Command	Status	Duration	Result
nx run-many -t build --parallel=3	✅ Succeeded	47s	View ↗

---

☁️ Nx Cloud last updated this comment at 2025-10-30 11:19:43 UTC

[delagen]

May be need to use simple concatenation

`${module}/subpath`

or pathe module

[ndelangen]

Thanks a lot for your contribution @delagen! @yannbf worked on a fix as well, we are going to be favoring usage of pathe instead, which takes care of path resolution on a windows-friendly manner: #32893

[delagen]

So closing in favour of storybook team preference