Update configuration and engine fixtures for identified resources

internal/engine/smoke_test.go

@@ -13,14 +13,14 @@ import (
 
 func engineSmokeBackendInput() configkit.Input {
 	return configkit.Input{Source: configkit.Mapping("smoke-test backend", map[string]any{
-		"backends": map[string]any{"test-backend": map[string]any{
+		"backends": []any{map[string]any{"id": "test-backend",
 			"endpoint": "https://test-backend.example/v1",
 			"smoke_tests": map[string]any{
 				"default_profile": "test-profile",
 				"authentication":  map[string]any{"kind": "none"},
 			},
 		}},
-		"profiles": map[string]any{"test-profile": map[string]any{
+		"profiles": []any{map[string]any{"id": "test-profile",
 			"backend": "test-backend",
 			"model":   "synthetic-model",
 		}},