Performance, TypeScript & Core Web Vitals

Type systems, strict TypeScript, structural typing, inference, unions, narrowing, generics, utility types, mapped types, conditional types, typed events, declarations, React prop APIs, forms, runtime schemas, error modeling, Next.js boundaries, typed telemetry, feature flags, testing contracts, main-thread responsiveness, workers, memory leaks, rendering pipeline, network waterfalls, caching, resource hints, mobile performance, hydration, streaming, dependency governance, security headers, secure storage, auth UX, resilient networking, source maps, release monitoring, incident triage, production readiness, accessibility, localization, SEO, PDF export, offline readiness, runtime performance, bundle strategy, profiling, Core Web Vitals, LCP, INP, CLS, field measurement, performance budgets, loading strategy, asset optimization, third-party governance, and debugging workflows.