ToleranceBreachEvent emitted when NPC stress exceeds per-seed threshold.
ToleranceBreached marker prevents duplicate events per episode, cleared
on recovery. check_tolerance_threshold system runs after update_mood,
integrates with mood FSM to push toward Hostile/Anxious. Background-tier
NPCs excluded. Unblocks #250 (triangle escalation).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>