Add collection input helper

configuration_sources.go

@@ -8,9 +8,25 @@ import (
 	"path/filepath"
 
 	"gitea.maximumdirect.net/eric/ConfigKit"
+	"gitea.maximumdirect.net/eric/promptkit/internal/domain"
 	"gitea.maximumdirect.net/eric/promptkit/internal/filecatalog"
 )
 
+// CollectionInput mounts source at the selected collection's configuration
+// destination and enables ConfigKit imports for that input. The source is not
+// read or validated until ConfigKit loads it. Callers may adjust the returned
+// input, including its filesystem context or imports setting.
+func CollectionInput(namespace string, source configkit.Source) (configkit.Input, error) {
+	if !domain.IsValidResourceNamespace(namespace) {
+		return configkit.Input{}, fmt.Errorf("%w: invalid collection namespace %q", ErrInvalidConfig, namespace)
+	}
+	return configkit.Input{
+		Source:      source,
+		Destination: configkit.Keys("collections", namespace),
+		Imports:     true,
+	}, nil
+}
+
 // DirectoryInputs selects the YAML files beneath an explicitly chosen host
 // directory as one strict-composition group. The returned order is deterministic;
 // it does not assign precedence among those files. Discovery is recursive over