Adapt Button to styled-react and remove sx

[pksjce]

Closes #6760

Current sx usage:

Button: 107
IconButton: 32

✅ sx usages are only in repos other than github-ui; those usages have been added to the tracking issue

Changelog

Removed

Remove support for sx from the Button, IconButton components, and associated stories, docs, and tests

Rollout strategy

• Patch release
• Minor release
• Major release; if selected, include a written rollout or migration plan
• None; if selected, include a brief description as to why

Testing & Reviewing

Merge checklist

• Added/updated tests
• Added/updated documentation
• Added/updated previews (Storybook)
• Changes are SSR compatible
• Tested in Chrome
• Tested in Firefox
• Tested in Safari
• Tested in Edge
• (GitHub staff only) Integration tests pass at github/github (Learn more about how to run integration tests)

[changeset-bot]

🦋 Changeset detected

Latest commit: 1fdd993

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

This PR includes changesets to release 2 packages

Name	Type
@primer/react	Major
@primer/styled-react	Major

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

[Copilot]

Pull Request Overview

This PR adapts the Button component to the styled-react package and removes the sx prop implementation from the main @primer/react package. The changes introduce custom styled-react implementations for Button, IconButton, and ActionMenu components that support the SxProp interface for backward compatibility.

Key changes:

• Creates new styled-react wrapper components for Button, ActionMenu, and IconButton
• Moves CSSCustomProperties type to a shared location in sx.ts
• Updates package exports to use the new styled-react implementations

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
packages/styled-react/src/sx.ts	Adds CSSCustomProperties type export for shared use
packages/styled-react/src/index.tsx	Updates exports to use new styled-react components instead of direct @primer/react exports
packages/styled-react/src/components/PageHeader.tsx	Updates import to use shared CSSCustomProperties type
packages/styled-react/src/components/IconButton.tsx	Creates new styled-react wrapper for IconButton with sx prop support
packages/styled-react/src/components/Button.tsx	Creates new styled-react wrapper for Button with custom sx prop handling
packages/styled-react/src/components/ActionMenu.tsx	Creates new styled-react wrapper for ActionMenu with sx prop support

[github-actions]

👋 Hi, this pull request contains changes to the source code that github/github depends on. If you are GitHub staff, we recommend testing these changes with github/github using the integration workflow. Thanks!

[github-actions]

👋 Hi, there are new commits since the last successful integration test. We recommend running the integration workflow once more, unless you are sure the new changes do not affect github/github. Thanks!

[github-actions]

👋 Hi, there are new commits since the last successful integration test. We recommend running the integration workflow once more, unless you are sure the new changes do not affect github/github. Thanks!

[github-actions]

👋 Hi, there are new commits since the last successful integration test. We recommend running the integration workflow once more, unless you are sure the new changes do not affect github/github. Thanks!

[primer-integration]

🟢 ci completed with status success.

[github-actions]

👋 Hi, there are new commits since the last successful integration test. We recommend running the integration workflow once more, unless you are sure the new changes do not affect github/github. Thanks!