Add opt-in configuration overrides

integrations/ckprompt/examples/composed/main_test.go

@@ -266,7 +266,7 @@ func TestBuildValidationRequestDefaultsOnlyAbsentVariables(t *testing.T) {
 	if !reflect.DeepEqual(got.Inputs, inputs) || !reflect.DeepEqual(seed.Request.Vars, explicit) {
 		t.Fatalf("seed bindings changed: built=%#v seed=%#v", got.Inputs, explicit)
 	}
-	key := applicationCacheKey{selection: seed.Selection, campaign: input.Campaign}
+	key := applicationCacheKey{config: seed.Selection.Config, overlay: seed.Selection.Overlay, campaign: input.Campaign}
 	cached := cache.applications[key]
 	if cached == nil {
 		t.Fatal("builder did not load application configuration into invocation state")