next-app-router-rsc-page-composition

Design, review, and refactor React Server Component architecture in Next.js App Router apps. Use when a task mentions RSCs, Server Components, Client Components, Suspense loading boundaries, skeletons, async page components, route/page composition, params/searchParams promises, cacheComponents, Server Functions/actions, useOptimistic, or feature-folder organization. Also use when the user wants a route split into a synchronous shell plus async regions, or wants existing client data tooling preserved instead of replaced.