Add framework documentation and offline example

README.md

@@ -11,8 +11,21 @@ The root `promptkit` package provides the supported public engine. Consumers
 can configure filesystem or in-memory prompt, profile, and schema sources,
 prepare requests without generation, run requests with the built-in
 OpenAI-compatible client, or inject their own model client and artifact reader.
-See the [Go package consumer guide](docs/consumers/pkg-promptkit.md) for the
-public workflow and contract.
+
+## Quickstart
+
+Run the maintained offline preparation example from the repository root:
+
+```sh
+go run ./examples/go-library/prepare
+```
+
+It loads a repository-local prompt, supplies an in-memory profile and inline
+input, and prints deterministic preparation metadata without contacting a
+provider or requiring credentials. Read the
+[example source](examples/go-library/prepare/main.go), the
+[Go package consumer guide](docs/consumers/pkg-promptkit.md), and the
+[framework format reference](docs/formats.md) to build a consumer workflow.
 
 Contributors should start with the [development guide](docs/development.md).
 The [architecture policy](docs/policy/architecture.md) defines the library