Function missing_for_agent 

pub fn missing_for_agent(
    refs: &Store,
    catalog: &Store,
    agent_id: &str,
    container: bool,
    reported: &[ObservedServer],
) -> Vec<String>

missing_servers for agent_id: what AgentMux would launch it with now (Store::effective_mcp_servers, which gives a container agent only what is switched on for containers) against what its CLI reported.