Ok So I got the oAuth at least taking me to the neato page for a login. Is that where you got stuck? I dont have any neato devices... so I could post this for some testing which it may just totally blow up after you auth. Or I could see if I can make an account with no devices and maybe it will let me do something further.
I see there is some code in here throwing errors as well, stuff trying to adjust the alarm status but it must need to be different for Hubitat. Its not stopping it from working though, it just wont be able to adjust the alarm until thats fixed.
Here is a quick and dirty way to share it so I dont have to mess around with gitHub just yet