React Performance Performance optimization patterns for React 18/19 and Next.js, adapted from Vercel Labs (MIT, v1.0.0). This skill organizes rules by priority and provides decision-tree guidance for active code review and refactoring. When to Activate - Writing or reviewing React/Next.js code for performance - Diagnosing slow page loads, slow interactions, or high CPU on the client - Auditing bundle size or Lighthouse Core Web Vitals regressions - Removing waterfalls in Server Components / API routes - Reducing client-side re-renders - Optimizing long lists, animations, or hydration - Auditi…