Reconcile module docs and release materials

registry.go

@@ -2,8 +2,10 @@ package commandkit
 
 import "fmt"
 
-// Register adds a batch of root commands to the application. The batch is
-// validated before the registry is changed.
+// Register adds a batch of root commands to the application. The complete batch
+// is validated before registry mutation; on error the registry and its derived
+// command metadata remain unchanged. A successful nonempty batch becomes
+// visible to later invocations. Command declarations remain reusable.
 func (a *App) Register(commands ...Command) error {
 	return a.installBatch(commands...)
 }