Cross-platform Determinism

The active voice contract is verified on the platforms covered by the CI matrix: Linux (ubuntu-latest) and macOS (macos-latest).

The CI job runs cargo test -p dootdoot-core --test golden_wav_hashes on both platforms. That test renders the fixed golden corpus, serializes the canonical WAV bytes, and compares each SHA-256 digest with golden_wav_hashes.tsv.

Passing CI means Linux and macOS produce identical hashes for every golden corpus entry. Any divergence is a sample-affecting determinism failure and must be investigated in the math, synthesis, quantization, or WAV serialization path before the contract can be considered green again.