Add framework documentation and offline example

docs/policy/architecture.md

@@ -9,8 +9,9 @@ implemented packages without redefining these rules.
 
 ## System Shape
 
-Promptkit is an importable Go library. It does not provide a runnable command,
-an HTTP service, or another application process.
+Promptkit is an importable Go library. It does not ship a command, an HTTP
+service, or another application process. Repository examples demonstrate
+library use but are not Promptkit applications or release artifacts.
 
 The module root contains package `promptkit`, which is the public facade. It
 provides the supported engine, configuration and source options, requests,
@@ -40,6 +41,10 @@ The implemented internal components consist of:
 - `internal/usecase`, which coordinates preparation and execution across the
   internal framework components.
 
+The `examples/go-library/prepare` package is a maintained downstream consumer
+of the root facade. It does not expose a library package or participate in
+internal assembly.
+
 The root facade assembles the internal repositories, renderer, validator,
 outbound client, and use-case runner while translating public values and
 errors at the library boundary. The defaults and renderer depend on the domain