Function self_scope 

pub fn self_scope() -> bool

Whether the operator opted into self-scoping: honoring the vault’s agent allow-tag policy for their OWN key, as if they were an agent. On via an explicit MURK_SELF_SCOPE, or implicitly in an agent_context (declaring MURK_AGENT binds you to the policy even with your own key). A no-op on a vault with no policy set.