Implement per-entity KnowledgeGraph component with BTreeMap storage for deterministic iteration (D-010). StableEntityId + EntityRegistry for entity identity across save/load. KnowledgeEventQueue + processing system for decoupled knowledge updates. Decay system runs once per game-minute. All types conform to D-041 canonical structs. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>