Signed evidence, not mystery callbacks.
Subscriptions accept public HTTPS endpoints only. Author resolves and rejects private/loopback destinations before dispatch, signs each canonical payload, and stores immutable delivery/attempt evidence.
author.project.updatedpublication.publishedreader.review.createdstory.chapter.releasedbusiness.rights.updatedbusiness.contract.activatedbusiness.submission.updatedbusiness.license.updatedSignature headers
x-leadstrium-event-idx-leadstrium-timestampx-leadstrium-signature: v1=<hmac-sha256>Signing material is derived at runtime; application records never contain CoreID secrets.