Player: full screen across videos, Hide, preferred quality; a Back button

Full screen: the page (document) goes full screen, not the player's box, so the next video (Next, a queue moving on, a media key, a voice assistant's "next track") is built inside it and full screen stays; body.theater lays the player over everything. Each new one shows its title and place in the queue over the picture for a few seconds, and a queue's countdown shows there too. Any page that isn't a video leaves full screen. A Hide button in the full-screen controls hides the episode or movie and goes to the next. Skip back and forward are both 10 s (buttons and media keys). Range sliders lose the text-box padding, so the volume reaches 100%.

Preferred quality: each user picks how Auto plays (Profile -> Video quality): auto, high (the file as it is or the top level first, back up to it sooner), medium (adaptive up to 720p) or low (up to 480p). Admins can set it as a user's default (Admin -> Users -> Default quality); the Best quality cap still wins, and the server applies the lower of the two. Migration PreferredQuality.

Back: a Back button in the top bar (not on home or sign-in). Pages are numbered in their history entries, so Back goes home instead of leaving the app when opened straight onto a page, and forward() keeps redirects from counting as a page. Docs, changelog, tests.

Co-Authored-By: Claude Opus 5.5 noreply@anthropic.com