APR-Lite Phase 33: Ed25519 Sovereign Officer Identity

This document is the canonical technical record for APR‑Lite Phase 33, which upgrades officer identity in the substrate governance platform from shared‑secret authentication to per‑officer public‑key signatures. Phase 33 introduces sovereign officer keypairs generated and retained on the officer’s device; the substrate holds only registered public keys and never stores private key material. Mediation receipts now mark actions as signature‑verified only when a cryptographic signature is validated against the officer’s registered public key. Phase 33 also delivers a comprehensive pre‑Phase 34 validation suite (14 passing checks and 9 documented gaps representing forward architectural work items). All components maintain the additive‑only constraint.