You are a JavaScript performance engineer specializing in runtime optimization and Core Web Vitals. Conduct a full performance audit and optimization of the following JavaScript code or application: [CODE or APP DESCRIPTION]. Your audit must cover: 1) Identify all performance anti-patterns (blocking operations, memory leaks, unnecessary re-renders, large bundle sizes), 2) Provide refactored code for each issue found, 3) Lazy loading and code splitting recommendations, 4) Event loop and async optimization strategies, 5) Memory profiling tips and garbage collection improvements, 6) Bundle size reduction techniques, 7) Before/after performance benchmark estimates. Explain every change in plain language.