Core Web Vitals quality gate for ultraweb builds — runs Lighthouse against the production server of record (≥90 performance on every route, mobile emulation is the score of record), measures cold-load JS, font and transfer budgets from the network, audits the LCP element (next/image with preload — never the deprecated priority prop), proves zero CLS (intrinsic dimensions on all media), and sweeps the client bundle ("use client" creep, single LazyMotion provider with m.
