Page-weight + render-blocking + image-dimension audit that approximates Core Web Vitals signals (LCP, INP, CLS) without a Google API key.
Fetches the rendered HTML, parses every <img>, <script>, <link>, and inline style, then estimates each Core Web Vitals signal from the page weight, render-blocking resource count, image-dimension hints, and font-loading strategy. Heuristic-only — for canonical numbers run PageSpeed Insights or field-data CrUX.