Send a custom event into the product's Journeys.

Requires automation:execute. The event arrives on the product's implicit "Banger API events" incoming webhook, created on the first event and listed with the other webhooks so Journeys can name its connection_id, or on connection_id, another active incoming webhook of the same product. From there it is processed exactly like an event posted to that webhook's URL: active Journeys whose trigger names the event type and connection enroll the person at email (or their configured audience), and Journeys whose goal names it stop that person's runs. Events can start already-approved Journeys, which send email. The event id makes the call idempotent: repeating it with the same body returns duplicate true; reusing it for a different body returns 409 webhook_event_id_reused.