feat: expose transaction failure stages and conservative outcomes

scripts/testdata/mysqlGenerated_test.go

@@ -20,7 +20,7 @@ func TestGeneratedMySQLConfigurationAndLifecycle(t *testing.T) {
 		t.Fatal(err)
 	}
 	if cfg.Database.User != "omni_test" || cfg.Database.TLS.ServerName != "localhost" || cfg.Database.Pool.MaxOpenConns != 2 {
-		t.Fatal("structured environment overlay was not applied")
+		t.Fatal("explicit database configuration references were not applied")
 	}
 	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
 	defer cancel()