Remove the deprecated SelectPanel experimental component

[hectahertz]

Closes https://github.com/github/primer/issues/5440

This pull request removes the deprecated SelectPanel2 component and all related files, stories, styles, and documentation from the codebase. It also updates references to its mock data in other story files and cleans up exports that previously included SelectPanel2 types and components.

Changelog

New

Changed/Removed

Component removal and cleanup:

• Deleted the entire SelectPanel2 component and its documentation file (SelectPanel.docs.json), removing all code, props, and subcomponent definitions.
• Removed all story files and story-specific CSS for SelectPanel2, including SelectPanel.stories.tsx, SelectPanel.playground.stories.tsx, SelectPanel.features.stories.module.css, and SelectPanel.module.css.

Exports and usage cleanup:

• Removed SelectPanel and its related types from the exports snapshot to ensure they are no longer part of the public API.
• Removed import of mockData from SelectPanel2 in ActionBar.examples.stories.tsx and replaced its usage with a hardcoded value to eliminate dependency on the deleted component.

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: 7a01dc4

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 removes the deprecated SelectPanel2 experimental component from the Primer React codebase. The component was previously deprecated and is now being completely removed as part of a major version release.

• Removes all SelectPanel2 component files, including implementation, tests, stories, and documentation
• Cleans up exports to remove SelectPanel types from the public API
• Updates dependent story files to remove references to deleted mock data

Reviewed Changes

Copilot reviewed 16 out of 16 changed files in this pull request and generated no comments.

File	Description
packages/react/src/experimental/index.ts	Removes export of SelectPanel2 from experimental package
packages/react/src/__tests__/__snapshots__/exports.test.ts.snap	Updates exports snapshot to remove SelectPanel types from public API
packages/react/src/ActionBar/ActionBar.examples.stories.tsx	Replaces SelectPanel2 mock data import with hardcoded value

[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]

size-limit report 📦

Path	Size
packages/react/dist/browser.esm.js	87.97 KB (0%)
packages/react/dist/browser.umd.js	88.08 KB (0%)

[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!

[francinelucca]

Removal code LGTM, what's the plan to get integration passing?

[francinelucca]

💅