* fix(version): detect docker under private cgroup namespaces
Docker defaults containers to a private cgroup namespace on cgroup v2
hosts (20.10+), which remaps /proc/self/cgroup to "0::/" and defeats
the runtime-name sniff, so compose installs report
deployment.mode=unknown. Check the container manager marker files
(/run/.containerenv, /.dockerenv) and the container env var first,
mirroring systemd's detect_container, and fall back to mountinfo when
the cgroup path is namespaced away.
* fix(version): drop the docker case from the container env check
docker never sets the container variable; /.dockerenv already covers it
Add metadata endpoint checks for openstack (covers OVHcloud), oracle,
alibaba, akamai (linode), ibm, and scaleway, and the FLY_APP_NAME
environment variable for fly.io. OpenStack must come before AWS since
it exposes an EC2-compatible endpoint.
