Migrate structural and inspection fixtures

internal/engine/sequence_combine_test.go

@@ -177,7 +177,7 @@ func TestCombineSequenceReplacementResetsLowerIdentity(t *testing.T) {
 }
 
 func TestCombineSequenceDifferentIdentityDeclarationsConflict(t *testing.T) {
-	declarations := extractSequenceDeclarationsYAML(t, `configkit:
+	declarations := extractSequenceDeclarationsYAML(t, `config:
   sequences:
     - destination: [items]
       key: id
@@ -256,7 +256,7 @@ func TestCombineSequenceClonesInputsAndDoesNotMutatePolicy(t *testing.T) {
 func TestCombineSequenceEquivalentIdentityFieldSets(t *testing.T) {
 	lower := sequenceFromYAML(t, "items: [{id: a, namespace: one}]\n")
 	higher := sequenceFromYAML(t, "items: [{namespace: one, id: b}]\n")
-	policy, diagnostics := resolveCollectionPolicy(Keys("items"), extractSequenceDeclarationsYAML(t, `configkit:
+	policy, diagnostics := resolveCollectionPolicy(Keys("items"), extractSequenceDeclarationsYAML(t, `config:
   sequences:
     - destination: [items]
       key: [namespace, id, id]