Harden item occurrence grounding

docs/internal/dnd.md

@@ -160,6 +160,11 @@ These projections are guidance only and never event evidence.
 The following differences are intentional and should remain explicit when a
 shared helper changes.
 
+Shared D&D text comparison is identified by `dnd.text_comparison.v1`. Any
+semantic change requires an explicit policy-version review for every affected
+identity, mapping, normalization, and validator policy; helper source is not a
+checkpoint fingerprint.
+
 | Lane | Intentional behavior |
 | --- | --- |
 | Spells | May use a spell-catalog overlay and optional NPC grounding; the catalog validator supplies domain-specific semantic checks. |