feat(audio): Phase 68 v2 - Implement algorithmic audio layers

Implemented:
- BioMusicAlgorithm: genotype-to-melody encoding
- AudioSystem: entropy extraction from PopulationStats
- AudioSystem: top lineage tracking + bio-music generation

Algorithm layers:
- Extract base_pitch: sensing_range -> musical tonal center
- Extract tempo_bpm: max_speed -> 60-180 BPM range
- Neural weights -> pitch offsets (12 semitone range)
- Connection count -> note duration

Tests: 51 passed (+3 algorithm-level tests)
Clippy: 0 warnings (without rodio features)

Author: pplmx