Enable a Service to Start on Boot

A service is installed with a unit file but will NOT come up after a reboot — it was never enabled. Your per-session assignment is in /root/case/assignment.env (SERVICE). Enable it so systemd starts it at boot. Enabling installs a symlink from the target's .wants directory to the unit (that's what systemctl enable does, per the unit's WantedBy=). systemd isn't PID 1 on a lab box, so grading reads that durable symlink rather than a live service — but systemctl is here, and enable writes the real thing. (Starting it now is a runtime action; what survives a reboot, and what's graded, is the enablement.)