RoleDefinition struct + generate_npc() seeds all 10 D-024 axes via
SimRng for deterministic generation. Constraint validation: no duplicate
relationship targets, stress < threshold, one routine entry per phase,
no contradictory personality trait pairs. Spawns fully-populated NPC
entity with 2-3 personality traits for tell system (#90).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
