aie-web-performancelisted

# Web Performance Optimizer Find what makes a page slow, then fix it. Produce a prioritized report with real byte savings and ready-to-use code — not generic advice. ## Why it matters Speed affects conversion, bounce rate, and search ranking. Google uses Core Web Vitals as a ranking signal (https://developers.google.com/search/docs/appearance/page-experience), and field data consistently ties faster pages to higher engagement and revenue. Optimize the metrics that reflect real user experience: LCP, INP, and CLS. ## When to use this skill The user says the site feels slow, has poor Lighthouse or Core Web Vitals scores, or wants to trim page weight. Works from a live URL or from a local project directory / source files. ## Inputs to gather - **URL or local path** to the site. - **Stack** if known (plain HTML, WordPress, React, Next.js, Vite, Astro, etc.) — it changes which build fixes apply. - **Target devices/browsers** and any specific concern (slow mobile, janky scroll, layout jump). ## Audit procedure Measure first, then attribute weight to the biggest offenders. For the full checklists and the exact commands and code snippets, read `reference/optimization-guide.md`. 1. **Baseline** — run Lighthouse (or read PageSpeed Insights field data) and record LCP, INP, CLS, FCP, TBT/TTI, and total transfer size. Note the LCP element specifically. 2. **Images** — usually 50-80% of page weight. Check dimensions vs. displayed size, compression, modern formats (AVIF/WebP), `src