AudienceSource is the same discriminated union as ListSource — same
kind discriminator, same payload shape — but named after its primary
downstream consumer (the Communications module). Defining it as a type
alias lets the Angular picker, the SendToAudience helper, and any
future audience-aware feature share one vocabulary with the list
operations stack without forcing them to import a "list" type.
AudienceSourceis the same discriminated union asListSource— samekinddiscriminator, same payload shape — but named after its primary downstream consumer (the Communications module). Defining it as a type alias lets the Angular picker, the SendToAudience helper, and any future audience-aware feature share one vocabulary with the list operations stack without forcing them to import a "list" type.