The previous boot-performance.test.mjs slept on setTimeout and measured nothing. This loads the live website in headless Chrome, reads boot.mjs's own telemetry (_bootTimings + a fetch hook on the "complete" boot-log event for the authoritative elapsedTotal), asserts a render surface actually appeared, captures per-file JS coverage + slowest resources, and writes a dated baseline JSON. Measures the WEBSITE boot, not the AC Native OS boot. Points at a system Chrome via executablePath (no version-pinned download), single instance (8GB-safe). Anon prod baseline: ~1.87s, 16-phase timeline. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>