nab v0.7.1 — speakerId compat fix

Patch release for the speakerId JSON deserialization fix found during the post-v0.7.0 live smoke test of the nab + hebb composition.

The bug

FluidAudio v0.13+ emits speakerId as a JSON string ("1") instead of an integer (1). This broke nab analyze --diarize on fresh FluidAudio installations.

The fix

Custom serde Visitor that accepts i64, u64, or str/String. Both forms deserialize to the same i32 speaker_id. Regression tests added.

Affected

All v0.7.0 users running FluidAudio v0.13+ (the current version installed by nab models fetch fluidaudio). Upgrade to v0.7.1.

Verification

nab analyze /tmp/test_30s.wav --audio-only --diarize --format json
# → 30s audio, 0.24s wall, 123x realtime, 2 speakers identified

Full smoke test of the nab + hebb composition passed after this fix.