Resolve profiles through built-in backends

engine.go

@@ -12,6 +12,7 @@ import (
 	"time"
 
 	artifactadapter "gitea.maximumdirect.net/eric/promptkit/internal/artifact"
+	"gitea.maximumdirect.net/eric/promptkit/internal/backend"
 	"gitea.maximumdirect.net/eric/promptkit/internal/defaults"
 	"gitea.maximumdirect.net/eric/promptkit/internal/llm"
 	"gitea.maximumdirect.net/eric/promptkit/internal/profile"
@@ -335,6 +336,11 @@ func NewEngine(cfg Config, opts ...Option) (*Engine, error) {
 		profiles = profile.NewOverlayRepository(options.memoryProfiles, profiles)
 	}
 
+	backendRegistry, err := backend.NewRegistry(nil)
+	if err != nil {
+		return nil, fmt.Errorf("%w: failed to construct backend registry: %v", ErrInvalidConfig, err)
+	}
+
 	validator := options.validator
 	if !options.validatorSource {
 		schemaDir := cfg.SchemaDir
@@ -365,6 +371,7 @@ func NewEngine(cfg Config, opts ...Option) (*Engine, error) {
 		runner: usecase.NewRunner(
 			promptDefs,
 			profiles,
+			backendRegistry,
 			artifacts,
 			prompt.NewGoRenderer(),
 			llmClient,