YouTube hard-caps a windowed embed to ~360p and only a real fullscreen lifts the
cap — after which the higher quality persists for the session. Since we can't set
quality via the (dead) API, coax it: on the first video opened per page session,
briefly enter fullscreen using the modal-open click's live user activation, then
exit back to the small player. Exits early once onPlaybackQualityChange reports the
quality actually rose (else after a ms cap). Module-scoped
hdUnlockDone flag makes it fire once per session (the unlock persists), with a
retry on the first overlay click if the open-click activation had expired. Cleaned
up on teardown so a mid-flash close can't leave the player stuck in fullscreen.
Best-effort — bandwidth still gates the actual bitrate.
peter
fcd58f12c9