Works on #31787

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 canary-release-pr.yml --field pr=<PR_NUMBER>

Greptile Summary

This PR implements a build system change to stop minifying the output across the entire Storybook monorepo. The primary changes involve modifying build scripts (scripts/build/build-package.ts and scripts/build/utils/generate-bundle.ts) to disable minification during the bundling process. As a result of these build system modifications, all 40+ package.json files across the monorepo have been automatically updated with new gitHead commit hashes that reference the commit containing the minification changes.

The change represents a shift in philosophy toward prioritizing developer experience over minimal bundle sizes. By removing minification, the distributed Storybook code will be more readable and easier to debug, which is particularly valuable for a development tool where users may need to inspect generated code or troubleshoot issues. The trade-off is larger bundle sizes, but this is acceptable for development tooling where debuggability is more important than size optimization.

Additionally, some packages show simplified export structures moving from conditional exports (import/require) to single default exports, and the addition of "type": "module" in some files, which aligns with the target branch sb10/esm-only indicating a broader transition to ESM-only distribution.

The gitHead field updates are automated metadata changes that occur during the build process to track which specific Git commit was used to generate each package, ensuring proper version tracking and build reproducibility across the monorepo.

Confidence score: 5/5

• This PR is very safe to merge as it only affects build tooling and package metadata without changing any functional code or APIs
• The changes are internal build optimizations that improve debugging experience with no breaking changes to public interfaces
• All changed files require minimal attention as they contain only automated gitHead updates and build configuration modifications