Apply spell normalization follow-up fixes

internal/cli/spell_catalog_identity_contract_test.go

@@ -190,8 +190,8 @@ func TestSemanticSpellCatalogFingerprintChangesCheckpointIdentityWithoutReferenc
 		return identity
 	}
 	first := identityFor(fingerprints)
-	changed := append([]pipeline.CheckpointFingerprint(nil), fingerprints...)
-	changed[0].Value = "sha256:changed-effective-catalog"
+	changed := replaceCheckpointFingerprintValue(t, fingerprints, normalizeSpellCatalogFingerprintName(), "sha256:changed-effective-catalog")
+	assertOnlyCheckpointFingerprintChanged(t, fingerprints, changed, normalizeSpellCatalogFingerprintName())
 	second := identityFor(changed)
 	if first.Digest == second.Digest || reflect.DeepEqual(first.ReferenceDigests, nil) || !reflect.DeepEqual(first.ReferenceDigests, second.ReferenceDigests) {
 		t.Fatalf("identities = %#v / %#v, want semantic invalidation with unchanged reference provenance", first, second)
@@ -251,8 +251,8 @@ func TestChangedSemanticSpellCatalogFingerprintCannotResumeRecordedCheckpoint(t
 	if restored, decision := sameLoader.Normalize("spells", spellnormalize.Key, normalizeDependencies); !decision.Reused || string(restored.Output.Artifact.Content) != `{"spell_casts":[]}` {
 		t.Fatalf("same normalize checkpoint = %#v, decision=%#v, want reuse", restored, decision)
 	}
-	changed := append([]pipeline.CheckpointFingerprint(nil), fingerprints...)
-	changed[0].Value = "sha256:changed-effective-catalog"
+	changed := replaceCheckpointFingerprintValue(t, fingerprints, normalizeSpellCatalogFingerprintName(), "sha256:changed-effective-catalog")
+	assertOnlyCheckpointFingerprintChanged(t, fingerprints, changed, normalizeSpellCatalogFingerprintName())
 	_, changedLoader, err := checkpointHandlersForRun(settings, Options{}, materialized, changed, []byte("same input"), nil, nil, "", "", true)
 	if err != nil {
 		t.Fatal(err)
@@ -265,6 +265,49 @@ func TestChangedSemanticSpellCatalogFingerprintCannotResumeRecordedCheckpoint(t
 	}
 }
 
+func normalizeSpellCatalogFingerprintName() string {
+	return "normalize:spells:" + spellnormalize.Key + ":effective_catalog"
+}
+
+func replaceCheckpointFingerprintValue(t *testing.T, fingerprints []pipeline.CheckpointFingerprint, name, value string) []pipeline.CheckpointFingerprint {
+	t.Helper()
+	changed := append([]pipeline.CheckpointFingerprint(nil), fingerprints...)
+	matches := 0
+	for index := range changed {
+		if changed[index].Name == name {
+			changed[index].Value = value
+			matches++
+		}
+	}
+	if matches != 1 {
+		t.Fatalf("checkpoint fingerprints = %#v, want exactly one fingerprint named %q", fingerprints, name)
+	}
+	return changed
+}
+
+func assertOnlyCheckpointFingerprintChanged(t *testing.T, before, after []pipeline.CheckpointFingerprint, changedName string) {
+	t.Helper()
+	if len(before) != len(after) {
+		t.Fatalf("fingerprint lengths = %d and %d, want equal", len(before), len(after))
+	}
+	changes := 0
+	for index := range before {
+		if before[index].Name != after[index].Name {
+			t.Fatalf("fingerprint[%d] name changed from %q to %q", index, before[index].Name, after[index].Name)
+		}
+		if before[index].Value == after[index].Value {
+			continue
+		}
+		changes++
+		if before[index].Name != changedName {
+			t.Fatalf("fingerprint %q changed unexpectedly", before[index].Name)
+		}
+	}
+	if changes != 1 {
+		t.Fatalf("fingerprints changed %d values, want exactly %q", changes, changedName)
+	}
+}
+
 func TestMaintainedProductionOverlayRunAlignsGroundingValidationAndProvenance(t *testing.T) {
 	outputRoot := filepath.Join(t.TempDir(), "output")
 	fake := &productionFakeLLMClient{spellResponse: productionSpellResponse("Aegis of Emberfall")}