Add family artifact selection and provenance

docs/cli.md

@@ -310,6 +310,12 @@ and precedence.
 
 ## `--artifacts` Selection Rules
 
+An artifact-family key selects all of its concrete character members. A
+concrete generated key selects only that member; mixed family and concrete
+selection is deduplicated and executed as concrete keys. The resulting plan
+and command output identify both the concrete key and, where applicable, its
+family and character ID.
+
 - accepted on `run`, `session plan`, `run-stage`, `analyze`, and `publish`;
 - repeatable and comma-separated values are combined, surrounding whitespace
   is removed, and duplicate names are collapsed;