Options for createMenuTriggerDismissBinding. The popover is
passed as a thunk because trigger directives resolve their popover
input lazily (after Angular binds inputs) - the binding cannot capture
the concrete reference at construction time.
Synchronous notification invoked from the DOM event handler after
the binding's lastSource signal is updated. Trigger directives
use it to call CngxMenuAnnouncer.announce(...) so screen readers
hear which path closed the menu. Runs from the same call stack as
the source DOM event - safe for signal reads.