Add opt-in PromptKit namespaces

docs/consumers/guide.md

@@ -339,6 +339,12 @@ same canonical request flags into their own input types. Each collection exposes
 individual handles and an `All` method, so a command can choose its applicable
 subset. The application decides how to apply the resulting values to its request.
 
+`ckprompt.WithNamespaces` enables standard resource namespace selection from
+application-supplied defaults. Loaders used with this option should leave view
+selection to the adapter. Without it, a loader can supply its own engine view.
+Direct callbacks receive the composed selection in their request. The
+[CLI reference](../cli.md#resource-namespace-selection) lists applicable flags.
+
 Catalog, named definition inspection, and requirements discovery do not render
 messages or load request artifacts. Concrete request validation follows native
 PromptKit preparation, which can resolve prompt/profile resources, load