AnnouncementPhraseOptions

Returns the phrase for a voiced transition between two snapshots, or null when this change carries nothing to announce. An empty string is a valid phrase (it arms "silence") - only null falls through to the spend check.

Phrase at mount, before any transition. Defaults to the empty string so initial state is visible, never announced.

Reactive snapshot the phrase derives from.

true when a transition must expire (spend) an armed phrase - e.g. a busy-state start whose later clear would otherwise re-announce the stale phrase through an aria-atomic region. Checked only when arm returned null.