Ground NPC occurrences by canonical names

internal/modules/dnd/npcs/registry/registry.go

@@ -31,8 +31,8 @@ type Registry struct {
 	canonical        []byte
 	digest           string
 	projectionDigest string
+	identityDigest   string
 	promptInput      contracts.LLMInputMaterial
-	identityInput    contracts.LLMInputMaterial
 	lookupByKey      map[string]int
 	lookupByID       map[string]int
 }
@@ -110,8 +110,8 @@ func emptyRegistry() *Registry {
 		list:             dnd.NPCRegistry{NPCs: []dnd.NPC{}},
 		canonical:        append([]byte(nil), content...),
 		projectionDigest: projectionDigest,
+		identityDigest:   projectionDigest,
 		promptInput:      contracts.NewLLMInputMaterial(ReferenceSlot, npccodec.MediaType, content, projectionDigest, ""),
-		identityInput:    contracts.NewLLMInputMaterial(ReferenceSlot, npccodec.MediaType, content, projectionDigest, ""),
 		lookupByKey:      map[string]int{},
 		lookupByID:       map[string]int{},
 	}
@@ -155,9 +155,9 @@ func loadRegistry(referenceContent []byte) (*Registry, error) {
 		canonical:        append([]byte(nil), content...),
 		digest:           digest,
 		projectionDigest: projectionDigest,
+		identityDigest:   identityProjectionDigest,
 		promptInput:      contracts.NewLLMInputMaterial(ReferenceSlot, npccodec.MediaType, projection, projectionDigest, ""),
 		lookupByKey:      lookupByKey,
-		identityInput:    contracts.NewLLMInputMaterial(ReferenceSlot, npccodec.MediaType, identityProjection, identityProjectionDigest, ""),
 		lookupByID:       lookupByID,
 	}, nil
 }
@@ -207,6 +207,15 @@ func (r *Registry) ProjectionDigest() string {
 	return r.projectionDigest
 }
 
+// IdentityDigest returns the SHA-256 digest of the ordered ID/name identity
+// projection. It binds durable identities without exposing them to the model.
+func (r *Registry) IdentityDigest() string {
+	if r == nil {
+		return ""
+	}
+	return r.identityDigest
+}
+
 // Count returns the number of validated NPC records.
 func (r *Registry) Count() int {
 	if r == nil {
@@ -224,15 +233,6 @@ func (r *Registry) PromptInput() contracts.LLMInputMaterial {
 	return r.promptInput.Clone()
 }
 
-// IdentityPromptInput returns the ordered ID/name projection for consumers
-// that must bind output records to exact registry identities.
-func (r *Registry) IdentityPromptInput() contracts.LLMInputMaterial {
-	if r == nil {
-		return contracts.LLMInputMaterial{}
-	}
-	return r.identityInput.Clone()
-}
-
 // Lookup returns the canonical NPC for an exact canonical-name match under the
 // NPC identity comparison policy.
 func (r *Registry) Lookup(value string) (dnd.NPC, bool) {