Bundle docs in the package and clean up private files

[rezrah]

Summary

Towards https://github.com/github/brand-experience/issues/248

Adds version-pinned, markdown-based documentation to the @primer/react-brand package, so that agents can retrieve documentation specific to their installed version of the library.

They will currently fetch documentation from primer.style/brand, but this is problematic because our production docs show unreleased features, and the installed version might be several minor versions behind.

Also cleans up the package files, particularly esm which was leaking some recipes and other things it shouldn't have.

🔗 Preview on unpkg

List of notable changes:

• Added a script to parse, transpile and copy all .mdx files in Next docs to the packages/react/docs folder, which is allow-listed through the NPM package. The script it kinda heavy only because may of our markdown files contain React components. We need to transpile those to make them readable. This isn't a simple copy/paste of our markdown files.
• Added some lightweight CI checks to make sure this continues to work correctly behind the scenes
• Backfilled a README, which was previously missing
• Fixed some package leakiness, now uses ALLOWLIST approach vs previous DENYLIST one
• Cleaned up some d.ts outputs in the UMD bundle, which were happening because tsc was emitting via Webpack loader instead of through tsc directly. Now consistent with ESM by doing it as a separate stage.

Steps to test:

1. Check the output of docs here, and report if you see anything that looks off in the generated markdown files.

Contributor checklist:

• All new and existing CI checks pass
• Tests prove that the feature works and covers both happy and unhappy paths
• Any drop in coverage, breaking changes or regressions have been documented above
• UI Changes contain new visual snapshots (generated by adding update snapshots label to the PR)
• All developer debugging and non-functional logging has been removed
• Related issues have been referenced in the PR description

Reviewer checklist:

• Check that pull request and proposed changes adhere to our contribution guidelines and code of conduct
• Check that tests prove the feature works and covers both happy and unhappy paths
• Check that there aren't other open Pull Requests for the same update/change

Screenshots:

[changeset-bot]

🦋 Changeset detected

Latest commit: 30ba823

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

This PR includes changesets to release 8 packages

Name	Type
@primer/react-brand	Minor
@primer/brand-docs	Minor
@primer/brand-css	Minor
@primer/brand-primitives	Minor
@primer/brand-e2e	Minor
@primer/brand-fonts	Minor
@primer/brand-config	Minor
@primer/brand-storybook	Minor

Not sure what this means? Click here to learn what changesets are.

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

[github-actions]

🟢 No design token changes found

[rezrah]

FYI these deps are already installed in the monorepo and not new. Prevents hoisting errors.

[Copilot]

Pull request overview

This pull request adds version-pinned, package-bundled Markdown documentation for @primer/react-brand (generated from the Next docs MDX) and tightens package outputs to prevent shipping internal-only files, particularly around declaration outputs and esm/lib contents.

Changes:

• Bundle Next docs MDX into packages/react/docs/ plus a root llms.txt index, and verify the bundled output (presence + size) in CI.
• Switch UMD type generation to a dedicated allowlist tsconfig.umd.json pass, and prevent webpack/ts-loader from emitting whole-tree declarations.
• Add/adjust package allowlist (files) and repo ignores so generated docs are packaged but not committed/linted/formatted.

Show a summary per file

File	Description
packages/react/webpack.config.js	Disables declaration emit during webpack bundling to avoid unscoped .d.ts output.
packages/react/tsconfig.umd.json	New allowlist tsconfig to emit only public-graph declarations into lib/.
packages/react/tsconfig.esm.json	Restricts ESM declaration emission scope to entry + ambient .d.ts.
packages/react/scripts/bundle-docs.mjs	New script to transpile MDX → Markdown and generate docs/ + llms.txt.
packages/react/scripts/verify-docs-bundle.mjs	New verification script to ensure docs are included in the packed tarball and within size limits.
packages/react/README.md	Adds package README pointing agents/users to bundled version-matched docs.
packages/react/package.json	Packages docs/ + llms.txt, adds bundling scripts/hooks, and adds MDX processing dependencies.
packages/react/eslint.config.mjs	Ignores generated docs/** within the package workspace.
packages/react/.prettierignore	Ignores generated docs/ and llms.txt.
packages/react/.gitignore	Ignores generated docs/ and llms.txt.
package-lock.json	Locks new unified/remark/mdast dependencies for docs bundling.
apps/next-docs/content/layout/Stack/react.mdx	Corrects source/storybook metadata to Stack (was Box).
apps/next-docs/content/forms/TextArea/index.mdx	Fixes storybook path and updates import example to @primer/react-brand.
apps/next-docs/content/components/Tooltip/index.mdx	Updates content but currently includes unresolved merge conflict markers.
apps/next-docs/content/components/SubdomainNavBar/index.mdx	Fixes default URL typo and table formatting.
apps/next-docs/content/components/Section/react.mdx	Fixes doc typos and corrects the as prop type union.
.github/workflows/ci.yml	Adds CI step to verify docs bundle output.
.changeset/exclude-internal-type-declarations.md	Changeset documenting filtered outputs for shipped bundles/types.
.changeset/bundle-version-pinned-docs.md	Changeset documenting bundled docs + llms.txt.

Copilot's findings

Comments suppressed due to low confidence (1)

apps/next-docs/content/components/Tooltip/index.mdx:71

• This file still contains unresolved git merge conflict markers (<<<<<<<, =======, >>>>>>>). MDX parsing/bundling will fail and the conflict text could ship into the bundled docs.

- [Popover](/components/Popover): For displaying more complex interactive content that appears when triggered
- [Button](/components/Button): Often used in conjunction with tooltips

• Files reviewed: 18/19 changed files
• Comments generated: 1

[github-actions]

🟢 Bundle size report

Check	Main	Branch	Change
UMD — full bundle (JS)	99.46 kB	99.46 kB	🟢 No change
UMD — full bundle (CSS)	65.46 kB	65.46 kB	🟢 No change
ESM — full bundle (JS + CSS)	1.50 MB	1.50 MB	🟢 No change
ESM — tree-shaken simple (Button)	68.33 kB	68.33 kB	🟢 No change
ESM — tree-shaken complex (ActionMenu)	77.11 kB	77.11 kB	🟢 No change

[github-actions]

🟢 Unit test coverage changes found

Unit test coverage has been updated through this PR.

Changes: 0 new tests, 0 removed tests, 0 improved, 1 decreased

Component/Hook	Statements	Functions	Branches	Change
IDE	91.6% 91.2%	97.4%	83.4% 82.8%	-0.7%

[github-actions]

🟢 No visual differences found

Our visual comparison tests did not find any differences in the UI.

[danielguillan]

LGTM!