The admin site (public-admin) is built and extracted into RemoteDir on
every deploy, but AdminSiteName/AdminAppPool defaulted to empty, so
deploy-iis-remote-apply.ps1 never stopped it before wiping RemoteDir -
it kept files open under the directory being wiped, causing the
intermittent Access Denied / residual-file failures. Pull the names
from deployinfo.txt (already the local per-environment config file)
so every deploy stops it automatically.