Document the bundled OpenRouter configuration

examples/go-library/prepare/main.go

@@ -63,7 +63,7 @@ func run(ctx context.Context, exampleDir string, out io.Writer) error {
 			{Inputs: []configkit.Input{support, review}},
 			{Inputs: []configkit.Input{override}},
 		},
-	}})
+	}}, promptkit.WithBundledOpenRouter(false)) // Keep this example's inventory caller-owned.
 	if err != nil {
 		return err
 	}