Add lookup.rs with voiced_behavior() — ready to wire into a behavior-serving
system once one exists (Q-058). Tell behaviors always passthrough (never
re-voiced). Cache miss returns base text (graceful degradation).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
MessagePack voice cache with per-zone persistence and version invalidation.
Priority work queue with crossbeam bounded channel, backpressure, pause/resume,
and zone-change reprioritization. Inference worker pool with empty output guard
and graceful degradation to base text.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>