Agent Skills: react-best-practices

React best practices from react.dev and Vercel. Use when: (1) Reviewing React code, (2) Debugging performance issues, (3) Optimizing bundle size, (4) Writing effects or state logic. Triggers on: React performance, re-render, bundle size, waterfalls, code splitting, memo, useCallback, useMemo, useEffect, SSR flicker, initial load slow, React Compiler, state structure, immutable update, setState array object.