Architect and scaffold Next.js applications (App Router) with production-grade project structure, rendering strategy, data fetching, and routing decisions. Use this whenever the user starts a new Next.js project, asks where a file/route/component should live, asks about server vs client components, asks about SSR/SSG/ISR/streaming, or is making structural decisions in a Next.js codebase. Also trigger on "how should I structure this Next.js app", "server actions", "route groups", "app router vs pages router".
