refactor(video-player): LTR timeline, unified buffer/progress layers, controls layout, remove ambient
- timeline: unified dir="ltr" container; buffer and progress as stacked absolute fills in correct z-order
- playhead: physical left property instead of insetInlineStart (fixes RTL mirroring)
- control bar: dir="ltr" explicit groups — left: play/rewind/volume/speed, right: theater/fullscreen
- rewind: replace flipped SkipBack with Rewind icon; seek indicator at physical right-8
- ambient effect: removed entirely (canvas, rAF loop, state, constants, toggle)
- settings menu: removed (speed accessible via pill; ambient gone)
- restart button: removed
ahp
f6ce2bd340