Add core/quality/source_map.py centralising each source's tier->AudioQuality
mapping (Tidal/HiFi tiers, Qobuz real kHz/bit-depth, Deezer codes, Amazon
codec/tier). Add TrackResult.set_quality() to merge a mapped AudioQuality
onto a result. Wire HiFi, Qobuz, Deezer, Tidal, Amazon search results to
stamp real sample_rate/bit_depth so the global ranker no longer relies on
crude kbps heuristics for streaming sources. Fixes Qobuz/Amazon display
labels ('FLAC 24-bit/192kHz', 'Lossless') breaking format derivation.
Tested: 22 passing (mappers + set_quality merge semantics).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>