Ports the Tauri radio_engine into a standalone, frontend-agnostic
crate so any client (Slint, TUI, CLI) can build and play a smart
radio without Tauri.
- New crate qbz-radio (builder + db + engine + tests), copied
verbatim from src-tauri/radio_engine with the only change being
the dependency rewrite: crate::api::{QobuzClient, Track,
TracksContainer} -> qbz_qobuz::QobuzClient + qbz_models. Depends
only on qbz-qobuz + qbz-models + rusqlite + dirs. All four engine
tests pass.
- QbzCore::create_smart_artist_radio builds the session pool + pulls
up to 50 track ids + resolves them to full tracks. The radio DB's
rusqlite Connection is !Send, so the build + pull run on
spawn_blocking threads (the async builder driven via block_on),
mirroring the Tauri command.
- The artist "radio" action (Spotlight RADIO card + artist radio)
now uses the smart builder (playback::play_smart_artist_radio);
album radio (Radio Stations) keeps the Qobuz /radio/album
endpoint, so both radio systems are in use. play_artist_radio
(Qobuz /radio/artist) is retained as the simpler alternative.
cc