001ef124a7
Against a plain usbipd (no control extension) the client synced the device list exactly once and then slept until shutdown: devices that changed busid on replug were never rediscovered, and in all-devices mode a worker that stopped had no path back. Refresh the devlist on an interval, re-probe the control extension every few minutes in case the server was upgraded, and warn that serial rules cannot match against servers whose listings carry no serial numbers.