Adds website/public/CNAME containing `mempalaceofficial.com` so the
VitePress build output always includes /CNAME in the Pages artifact.
Without this, the custom-domain setting is only held in the repo's
Pages API config — if it ever drifts (manual edit, org move, workflow
change), the site reverts to <org>.github.io with no record in source.
Note: this does not fix the current site outage. The root cause is DNS
— mempalaceofficial.com has no A/AAAA/CNAME records pointing at GitHub
Pages IPs. That has to be fixed at the registrar. This commit is the
belt-and-suspenders so that once DNS is back, the domain is pinned in
source and the next workflow refactor can't accidentally drop it.
Igor Lins e Silva