Closes the open gate from 2026-04-24-195210 handoff. Captures:
- two-host deploy topology trap (steel141 vs caddy CT) and corrected workflow
- viewport-gated visual: toolbar is display:none above 900px, so desktop
reloads were byte-for-byte identical regardless of toolbar.js version
- diagnostic chain that ruled out cache, service worker, and CDN before
finding the viewport gate
- remaining work: real-device mobile acceptance test only
Validator score: 90/100 (READY).