Extract visibility geometry into a separate system behind a PerceptionQuery trait, enabling D-017 perception mode swapping. Two-stage pipeline: compute_visibility_geometry writes to VisibilityGeometry resource, compute_observer_snapshot reads it. Remove KnowledgeGraph from compute_nearby_interactions (simulation phase boundary violation). Verb availability stays in simulation; POI-based priority adjustment moves to observer via apply_poi_verb_priority helper. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>