- bridge measures the BODY (scrollHeight + rect + margins) instead of the
viewport-clamped documentElement — documentElement.scrollHeight latches
at the parent's own height, so demos could grow but never shrink on
window resize (owner-reported); smoke: 1036 → 2386 → 1036 px
- invert now PERSISTS as details.ui.inverted on the steer record, written
by the silent artifact-ui route (dismissal pattern: no wake, no SSE) and
seeded through the projection (SubagentArtifactData.ui); survives
navigation + reload, never enters teacher context or exports
- invert restyled as the house Toggle switch (settings controls) on both
cards; demo header is the caption grammar: 'INTERACTIVE DEMO — title'
left (title normal-case, same size/tracking), switch + download far
right; figure header: label left, switch/download/open far right
1439 tests green (route + pure-seam pins added); live smoke passed
