Sub-ticket of MSG-38 POST /unregister route: deregister permanence for VENUSINF waves - {agent,caller,[bearer]}; txn validate->capture-PM-AROs->deleteAroByAgent->electPm-each->deleteRosterRow; PRESERVE cursors (optional purge_cursor:true default false); idempotent 200 already_absent; auth self-dereg ungated + admin-dereg edge-bearer interim soft-dep #599; HTTP-only (no MCP tool). Replaces hand-SQL roster DELETE dereg-at-cutover. · llmmsg-srv