- numa.service: User=numa + CAP_NET_BIND_SERVICE + sandboxing block
(ProtectSystem=strict, PrivateTmp, seccomp @system-service, etc)
- install_service_linux: create numa system user + chown data_dir
before first start so TLS-cert generation and state writes land
on a numa-owned tree
Runtime verified root-free on Linux — network_watch_loop only reads
/etc/resolv.conf; all system-DNS mutation stays in the installer,
which continues to run as root via sudo.