Function catch_up 

async fn catch_up(
    base: &str,
    token: &str,
    http: &Client,
    agents: &Arc<Mutex<HashSet<String>>>,
    mstore: &Arc<Store>,
) -> bool

Pull pending injections for every registered agent now. The same work an InjectAvailable wake does, run on connect, when an agent is added, and on a timer (CATCH_UP_EVERY) so a missed wake costs minutes at worst. Returns true when the session should reconnect (the shared token expired).