Post retraction and operator removal

Purpose: Delete a post's prose from the current tree while retaining a receipt that describes the removal on its own. Scenario: A signed retraction request or a local operator deletion is accepted by an authenticated entry point; the post and signature files are removed, a shared Key: value receipt is written and committed, routes serve the deletion notice at the post's path and at every historical commit, and the read model is refreshed. The sweep retires derived copies; the history purge later removes the prose from Git history. Sources: removal acceptance record, post retraction record, accepted removal reader (source unavailable), retracted paths (source unavailable), operator reference, sweep reference. Known limitation: Acceptance deletes current content only; history, backups and external copies are separate concerns (history purge).