The container menu lists stopped containers too, and pct exec on one exits
255: 12 of 41 failures in three days. Start it the way add-netbird-lxc does
and wait for its default route.
The install runs under bash, which an Alpine container from the template does
not have; lxc-attach then exits 127 before the Alpine branch is reached.
Install bash there first, and stop with a clear message on any OS other than
Debian, Ubuntu or Alpine instead of failing on apt-get.