- Simple mode renders video and audio with the Studio player through
mountStudioPlayerHost, which honours the floating viewer's player-host
contract (togglePlay / stepFrames / destroy handle, inner media element
for mute/speed persistence) and releases media on teardown. Falls back
to the legacy player for images, 3D, compare modes, mount failures
and the "classic viewer" setting.
- StudioPlayer gains initial mute/speed, a compact width-aware variant
and an autoplay that retries muted when sound is blocked.
- CSS-only refresh of the floating window aligned with the Studio
viewer; popped-out / desktop-expanded windows stay square.