Harden item occurrence grounding

internal/modules/dnd/locations/identity/identity.go

@@ -10,8 +10,7 @@ import (
 
 	"gitea.maximumdirect.net/eric/notarius/internal/core/source"
 	"gitea.maximumdirect.net/eric/notarius/internal/modules/dnd"
-	"golang.org/x/text/cases"
-	"golang.org/x/text/unicode/norm"
+	"gitea.maximumdirect.net/eric/notarius/internal/modules/dnd/shared"
 )
 
 const (
@@ -51,17 +50,7 @@ func NormalizeDisplay(value string) string {
 
 // ComparisonKey returns the stable key used for location identity comparisons.
 func ComparisonKey(value string) string {
-	value = norm.NFKC.String(value)
-	value = strings.Map(func(r rune) rune {
-		switch r {
-		case '\u2018', '\u2019', '\u02bc':
-			return '\''
-		default:
-			return r
-		}
-	}, value)
-	value = strings.Join(strings.Fields(value), " ")
-	return cases.Fold().String(value)
+	return shared.ComparisonKey(value)
 }
 
 // DeriveID derives a location ID from name and the earliest canonical evidence