Two micro-risk mitigations documented:
1. dedup_group_id: Format "{business_id}:{hash}" to prevent
cross-tenant collision on similar reviews.
2. Sentinel conventions: 'ALL' (spatial) vs 'all' (semantic).
Case matters — do not normalize.
Spec frozen as v3.1.2.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>