The app now holds one RadioProvider and asks it for stations, song history and stream URLs instead of importing SomaFM's HTTP client directly.
- models.py: provider-neutral Song/Station plus the shared parsers every catalogue needs (Station.provider/.uid keep ids unique once there is more than one).
- providers/base.py: the RadioProvider interface and the toolkit it needs in practice - httpx client factory, .pls/.m3u resolution with an 8h disk cache, and a default stream_candidates() strategy.
- providers/somafm/: everything SomaFM-specific (channels.json, songs/<id>.json, PLS layout, guessed icecast mirrors) behind SomaFMProvider.
- providers/__init__.py: registry, get_provider() and --provider, remembered in the config file.
Widgets render branding, splash copy and the help credits from the active provider, so a second catalogue needs no UI changes; with SomaFM selected the screen is byte-identical to before.
macOS has no D-Bus/MPRIS: the audio engine is what the OS media UI talks
to. mpv's Cocoa backend registers with MPRemoteCommandCenter and
MPNowPlayingInfoCenter, so it already publishes the live ICY title and
receives the media keys.
Add a platform-neutral media session (mediasession.py) so the app keeps a
single interface: MprisService on D-Bus platforms, NowPlayingSession on
macOS. Map mpv's NEXT/PREV/PLAY/PLAYONLY/PAUSEONLY/STOP keys onto
script-messages and read them back as client-message IPC events, so the
hardware media keys and Control Center drive the TUI (station changes,
play/pause/stop) instead of fighting it.
--no-mpris (now also --no-media) disables the media keys too. macOS-only
mpv options are gated on sys.platform so the Linux command line is
unchanged; mpv aborts on unknown flags.
beefcarver