Dynamic AddressBook Update Mechanism

Create the mechanism for initiating a dynamic update to the address book.
* Setting and Clearing new AddressBook in `DualState`?
* Any validation?

Start by locating DualState and the existing AddressBook lifecycle and update entry points. Review how state changes are initiated and validated, then clarify whether this work should set, clear, or replace the AddressBook and what validation is required. Done means the dynamic update mechanism and its validation behavior are explicitly defined and implemented.

Written by the indexing model from the issue text.