Ya, so I was dumb...I have a local dev instance and a staging server. I was playing around with some things and forgot to switch the theme back to vanilla which explains why I was missing the navbar for the login screen...boo me.
But yes, thanks for pointing that out. The template engine and middleware are making a lot more sense now after looking through the source for the last 2 days...
I'm going to start looking to add/update the documentation here soon...some of the stuff can drive you crazy if you aren't familiar with the version changes.
Also, after reading through most of core at this point I have to say it's an impressive piece of kit. Thumbs up to the core devs. @julian @baris @psychobunny