Publish the Promptkit engine facade

doc.go

@@ -1,2 +1,8 @@
-// Package promptkit defines the public package boundary for the Promptkit Go module.
+// Package promptkit provides an embeddable engine for preparing and executing
+// prompt-defined LLM workflows.
+//
+// Applications construct an Engine with NewEngine, select filesystem or
+// in-memory definition sources with options, and use Prepare or Run to execute
+// requests. Concrete repositories, validators, and outbound clients remain
+// internal implementation details.
 package promptkit