if worker's session timeout-expired, cacdrive crash rather than re-login

[divinity76]

as the title says, in this scenario, cacdrive just crash.

what should happen, however: the worker should automatically re-login, and re-attempt whatever action was attempted when the logout was noticed.

• either that, or make sure to always ping cac at an appropriate interval just to keep the session alive. (this would be much easier to implement, albeit slightly less robust. an optimal solution would probably be a combination.)