An input-latency probe on the inject channel: a click, key, text insert or script marks the time and the GPU publish logs the first frame with changed rows after it. Measured on the device: jihad-anim-css.html 26-31 fps reading only its 160 changed rows; eight keys typed into jihad-input-echo.html reach a published frame in 22-62 ms and five DOM edits in 26-70 ms (the chart's 106 ms); jihad-scroll-js.html followed at 10.7-13.9 fps (the chart's 9). Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01J67ZH8aYy8uzhgZDZ6Nvx9