Closes #33197, #32835

What I did

Due to dynamically computing the CWD, patterns starting with ! (e.g., !(_atoms)/**/*) were incorrectly interpreted by globby as negation patterns (exclusions) instead of extended globs (inclusions).

This change restores the custom CWD logic and prepends ./ to any pattern beginning with !. This ensures globby interprets the pattern as a relative file path using extended glob syntax (e.g., ./!(_atoms)/**/*), allowing the intended files to be matched correctly.

Since the original issue did not provide a reproduction repository, I created a sandbox based on the description to verify the fix:
https://github.com/ia319/storybook-PR-Preview-Sandbox/tree/main/negated-glob-patterns

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>

Summary by CodeRabbit

• Bug Fixes
  • Improved glob pattern matching and directory handling to ensure reliable file discovery across different working directory configurations.

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