Webhooks:规范
使用 HMAC 对原始正文进行签名的出站 Webhook,具有稳定的交付身份、有限重试后进入死信队列、容忍时钟偏差的时间戳,以及回调 URL 中无秘密材料。
Domain mutations and outbox rows share one database transaction; a relay publishes at-least-once; consumers are idempotent; writing the database and a broker independently without an outbox is forbidden.