Tidal, Qobuz, HiFi, and Deezer results were blindly taking the first
API result with minimal validation. Now all streaming sources use
score_track_match() — same 60% title / 30% artist / 10% duration
weighting as Soulseek, plus version detection penalties.
- web_server.py get_valid_candidates(): replaced loose title-sim check
with matching engine scoring, version penalty for live/remix/acoustic
- download_orchestrator.py: optional expected_track param enables
scoring in search_and_download_best (backward compatible)
- sync_service.py: passes spotify_track for validation
- Fixed wrong class name (MusicMatchingEngine not MatchingEngine)