so it turns out you can use Apache mod_proxy to proxy to an IPv6 link-local address, but it's a bit roundabout.
in /etc/hosts:
fe80::2%vm.cgit cgit-backend.internal
in Apache:
<Location />
ProxyPass http://cgit-backend.internal:80/
</Location>
i feel like there should be a better method to do this. any suggestions?
trying to ProxyPass to "http://[fe80::2%vm.cgit]:80" doesn't work:
AH01083: error parsing URL http://[fe80::2%vm.cgit]:80: Invalid host/port