Improve D&D registry normalization efficiency

internal/modules/dnd/normalize/itemregistry/normalizer.go

@@ -241,20 +241,15 @@ func normalizeRecord(input dnd.Item, order shared.SourceRefOrder) (dnd.Item, boo
 
 func comparisonNameGroups(records []normalizedRecord) [][]int {
 	groups := make([][]int, 0, len(records))
+	groupPositions := make(map[string]int, len(records))
 	for index, record := range records {
 		key := identity.ComparisonKey(record.item.Name)
-		found := false
-		for groupIndex, members := range groups {
-			first := records[members[0]]
-			if identity.ComparisonKey(first.item.Name) == key {
-				groups[groupIndex] = append(groups[groupIndex], index)
-				found = true
-				break
-			}
-		}
-		if !found {
-			groups = append(groups, []int{index})
+		if groupIndex, found := groupPositions[key]; found {
+			groups[groupIndex] = append(groups[groupIndex], index)
+			continue
 		}
+		groupPositions[key] = len(groups)
+		groups = append(groups, []int{index})
 	}
 	return groups
 }