Feature: Cryptographic Audit Trail — SHA-256 Hash-Chained Action Log for Tamper-Proof Agent Accountability (inspired by OpenFang)

#487 Fixed

Feature: Cryptographic Audit Trail — SHA-256 Hash-Chained Action Log for Tamper-Proof Agent Accountability (inspired by OpenFang)

This closed issue proposed adding a cryptographic, SHA-256 hash-chained audit trail for agent actions in Hermes, inspired by the OpenFang project's tamper-evident logging design.