v0.12.133: @newsroom.writer: governs, enforces, attests

Governs, enforces, attests: Dinis's answer to a summary of how ruv.sgit and an attestation layer fit together, written without naming its author or quoting it. An Agent Behaviour Policy governs and names the enforcer; rules are kept at three levels, the prompt, hooks, or a third-party system that blocks (recommended), which in ruv.sgit is Ruflo's policy engine in enforce mode, writing a decision receipt that an sgit vault keeps; an attestation layer signs what was assured so a customer, auditor or insurer can verify it. Four figures: the stack (at-stack), the three levels (at-levels), the same question without and with attestation (at-without-with), and one action through the stack (at-flow).