I was thinking of doing this (ircd, in golang, with an integrated bouncer and ircv3 features) myself, so I'm glad someone else has.

The place I was planning to diverge was to make a c2s bouncer api that could be used via http, so that mobile clients could work and stay logged in even when the app was backgrounded. That may still be possible with the bouncer protocol instead of http, but if you do it with http then you can make a js web client too, for a sort of self hosted irccloud.