Persistent per-platform mode that plays only the audio track to save
bandwidth and speed up loads. When enabled, stream selection picks the
best audio-only stream (preferred language, codec, bitrate) and never
fetches the video URL; toggling mid-video reloads at the current
position using the quality-switch path (live vid=no toggling is avoided
due to A/V desync).
- Toggle row in the player quality/settings sheet on iOS, macOS and
tvOS, next to lock controls
- New audioMode control button type (red when active) for player
controls and mini player layouts
- Picking a video quality explicitly turns the mode off; audio track
picks keep it on and now work while audio-only is playing
- Stream URL refresh preserves audio-only playback instead of
resurrecting video
- Queue preloads and history entries resolved before a toggle are
discarded so selection re-runs with the current mode
- tvOS player shows the video thumbnail instead of a black screen
during audio-only playback
- PiP button hidden for audio-only streams
Playback menu seek items now follow the durations from the active player
controls preset instead of hardcoded 10s/30s labels. AppEnvironment caches
the active preset's center settings (refreshed on preset change
notifications) so menu commands can read them synchronously.
Add secondary seek durations (default 30s) to CenterSectionSettings,
configurable on macOS in Seek Durations settings, used by Shift+arrows in
the player and Cmd+Shift+arrows in the Playback menu.
Also let Cmd-based key equivalents pass through the player keyboard
monitor so menu shortcuts (e.g. Cmd+Option+arrow previous/next video)
work while the player window has focus, and unify macOS built-in preset
primary seek at 10s to match iOS/tvOS (built-in presets version 8).
