If you're the only one using it, you could just publish the source and let us review it. Worst case we find some terrible flaw and you have to stop using it for a bit while you fix it.
But I can't imagine any big vulnerabilities in a local frontend anyway? I'd be more worried about accidentally sending/resending requests and generating unnecessary load for the server. For authentication it's hard to mess up as long as you're not sending passwords to servers other than the one you're trying to log in.