Function load_persisted_conversation_policy 

pub async fn load_persisted_conversation_policy(
    persistence: Option<&Arc<dyn PersistenceLayer>>,
    owner_id: &str,
    conversation_id: &str,
) -> Option<RunPolicy>

Load the durable conversation-scoped policy from persistence, if present.

Returns None when persistence is absent, the record is missing, or the load fails (a load error is logged and treated as “inherit”). Callers that also maintain an in-memory conversation policy (e.g. the service path) resolve that fallback themselves and pass the result as the conversation scope.