A shared /watch video stopped the moment you backgrounded the browser on iOS (Safari/Brave suspend a
<video>), while an audio-only share kept playing — the user wanted YouTube-style background playback
for video too. Route the element's same-origin audio through a Web Audio graph (once that graph is
live, iOS keeps the audio session running in the background while the frame freezes) and add Media
Session metadata + play/pause handlers for lock-screen controls. Set up lazily on first play (the
gesture an AudioContext needs) and only once. Best-effort — any unsupported bit falls back to the
plain <video>. Background continuation itself is an iOS behaviour only real-device UAT can confirm.