T5: 1:1 port of the artist_vectors SuggestionsEngine into qbz-reco (~880 lines;
structure matches the Tauri source function-for-function). generate_suggestions:
ensure each seed vector (builder.ensure_vector), gate on a non-empty combined
playlist vector, rank candidates by DIRECT summed relationship weight via
store.get_all_related_artists (NOT cosine/find_nearest, D3), then pull + dedup +
exclude tracks from Qobuz with the validate_qobuz_artist + has_incompatible_genre
gates and optional reason strings. Keeps Tauri's Arc<Mutex>/RwLock ownership
(Send-safe). DTO reconciliation: crate::api -> qbz_qobuz::QobuzClient +
qbz_models::Track (4 Qobuz calls mapped to real signatures, field-by-field).
Adds rand (0.10, workspace) + qbz-models deps. 23 qbz-reco tests green.
cc
vicrodh
90a8240671