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>
Split observer/mod.rs (820 lines) into production code (244 lines) and
tests (480 lines). Reduces module size per Hoshe #3 review item.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>