Golden targets: make golden-diff shows color diff if simulation output changed, make golden-update regenerates and stages for review. Checklist schema: JSON Schema for 7 condition types evaluable from ObserverSnapshot. Per-room YAML checklists for 3 Gauntlet rooms plus cross-room checks. Validation script + make checklist-validate/generate. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>