YouTube-parity hotkeys. Shift+. (">") steps playback up by 0.25 to a
max of 2x; Shift+, ("<") steps it down to a min of 0.25x. "." / ","
alone also work when the browser doesn't surface Shift for the
underlying character — e.g. non-US keyboard layouts.
Theater (T), PiP (I), Fullscreen (F), Play/pause (K / space), Mute
(M), Seek (J / L / arrows), % seek (0-9) were already wired — this
closes the remaining Phase 4 hotkey gap.
Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>
