Template
env.IMAGE: __PROJECT_NAME__ is only substituted with a real, lowercase
project name when a repo is *generated* from this template. On the
template repo itself it's still the literal placeholder, which
buildah/Docker reject outright ("repository name must be lowercase") --
build (and therefore deploy) can never succeed here no matter what else
changes. Gate both on github.repository != this template's own path so
the template's CI reads green on what it actually validates: the check
job (lint/vet/test), the thing every generated repo inherits.