chore: cleanup sx prop

[francinelucca]

Changelog

New

• add type ThemeColorPaths, type ThemeShadowPaths

Removed

• remove sx, SxProp, exports from @primer/react

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: 2af81e5

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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[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!

[primer-integration]

👋 Hi from github/github-ui! Your integration PR is ready: https://github.com/github/github-ui/pull/4983

[primer-integration]

🟢 ci completed with status success.

[Copilot]

Pull Request Overview

This PR implements a cleanup of the sx prop functionality by reorganizing its location and removing certain exports from the main @primer/react package. The changes are part of a deprecation strategy where sx prop functionality is being consolidated in the @primer/styled-react package while being removed from the primary React package.

Key changes:

• Moves sx prop implementation from @primer/react to @primer/styled-react package
• Removes sx, SxProp, merge, and related type exports from @primer/react
• Adds ThemeColorPaths and ThemeShadowPaths type exports to @primer/react

Reviewed Changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
packages/styled-react/src/sx.ts	Replaces simple re-export with full sx prop implementation including types and utilities
packages/styled-react/src/styled-props.ts	Removes BetterSystemStyleObject export that's now available from sx.ts
packages/styled-react/src/index.tsx	Updates exports to include merge and BetterSystemStyleObject from local sx module
packages/styled-react/src/components/*.tsx	Updates import statements to use local sx and SxProp instead of importing from @primer/react
packages/react/src/sx.ts	Removes merge import and export since it's no longer needed
packages/react/src/index.ts	Removes sx related exports and adds theme type exports
packages/react/src/__tests__/__snapshots__/exports.test.ts.snap	Updates snapshot to reflect removed and added exports
.changeset/mean-kangaroos-count.md	Documents the breaking changes for versioning

[Copilot]

Import should use named import for consistency. Change import sx, {type SxProp} to import {sx, type SxProp} to match the pattern used in other component files.

Suggested change

	import sx, {type SxProp} from '../sx'
	import {sx, type SxProp} from '../sx'