- Image lazy loading: IntersectionObserver + blur-up placeholder - Request deduplication: in-flight Promise sharing by URL+body key - Prefetch on hover: 5-minute cache for pre-fetched detail data - Memory leak audit: useCleanup() tracks intervals/listeners/observers - Background sync queue: retry failed IDB saves on visibility change - Bundle splitting: composable architecture enables tree-shaking Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>