hook property

The data and the roles of the app, as the hooks of its roles got them when the harness rendered it: the data of the roles that applies, the present roles, the context of the harness and the choices of the roles; null without an app.

A role builds the input of its hooks from it with Role.hookInput, so a test reads what the modules gave a role, and what the role chose, as every provider of the role gets it, whichever module provides it.