Function evaluate_commit_policy 

pub fn evaluate_commit_policy(
    ctx: &AuthsContext,
    root_did: &str,
    signer_did: &str,
    now: DateTime<Utc>,
) -> Result<PolicyOutcome, CommitTrustError>

Evaluate the commit signer against the root’s org policy (if any).

Loads the policy anchored by root_did and evaluates a grant-based context for signer_did. A root with no anchored policy yields PolicyOutcome::NoPolicy (legacy allow, recorded). Pure over the registry + injected now.

Args:

• ctx: Auths context (registry).
• root_did: The commit’s Auths-Id (the policy authority).
• signer_did: The commit’s Auths-Device (the signer being gated).
• now: Current time, injected at the boundary.