Delete an audience

Soft-deletes the audience by marking it as archived. The audience is excluded from GET /v1/audiences list responses and cannot be used for new deliveries, but its delivery history remains accessible via GET /v1/audiences/{id}/deliveries.

In-flight deliveries that are already processing are not cancelled — they will complete normally. New delivery requests against an archived audience are rejected with 404.

To restore an archived audience, use PATCH /v1/audiences/{id} with { "status": "active" }. Idempotent — deleting an already-archived audience returns 204 without error. The archive action emits no billable usage. Requires 'creator' scope.