A from-the-ground-up reference for the audio modality: waveform → canonicalize
→ frames → acoustic lexer → typed AudioIR → operators/rotors → (32,) versor,
with every spec/constant grounded in the code (PR-2..PR-6 stack).
Includes the three-way clarification of learned models: embeddings (never),
audio specs (CORE's own DSP, not any model), text transcript (Whisper/NeMo as
typed labels only). Documents the substrate-vs-evidence split, the verbatim
teacher policy, current inert/gated status, and the 'scrutinise the consumer'
flag. Cross-links ADR-0180/0181 + spec + eval-plan. Lives at
docs/audio_pipeline_overview.md.
