docs(composition): explain compound component client boundaries

Summary

Closes #147. Explain the React Server Component boundary for compound component objects in the composition rule, and regenerate the compiled guide with the existing builder.

Dot notation remains valid within client modules. A Server Component importing an object from a client entry point must instead import directly exported component parts, or render a client wrapper that composes them. The guidance keeps context consumers/event handlers on the client while allowing the page/layout to remain a Server Component.

Only the source rule and its generated AGENTS.md change. No public skill names, build scripts, workflow definitions, dependencies, or lock files change.

Validation

• Disposable Next.js 16.4.3 / React 19.3.0 App Router fixture, production webpack build: importing the compound object in the Server Component failed at prerendering; importing the directly exported component passed and produced the expected static HTML.
• Regenerated the composition guide; a second build produced identical bytes.
• Parsed all 8 composition rules; checked that the edited rule preserves all 5 examples (including its original compound Usage example) and both primary references.
• Existing default validator passed for all 70 React best-practice rules. This validator targets the default React skill, not the composition skill.
• Discovery-index build passed for all 9 skills; git diff check passed.

Build tooling was installed with pnpm 8.15.9 to use the checked-in v6 lockfile without rewriting it. No claim is made about every composition example or Turbopack; the executable reproduction uses a minimal boundary example and webpack. The existing React-only CI path filter does not cover composition, so its build was checked separately locally.

References

• https://react.dev/reference/rsc/use-client
• https://nextjs.org/docs/app/getting-started/server-and-client-components#context-providers

AI assistance

Codex assisted with investigation, the documentation changes, fixture/build validation and this description.

Hosted status

At 86a186157bd8c04c2f5ff08ea98bff1a5fff2bde, security checks succeed, while Agent Skills Discovery is action_required pending maintainer approval. The external Vercel deployment status fails with Authorization required to deploy, and its bot requests a Vercel team member to authorize it. Maintainer help was requested; the PR is not represented as fully green.