- systemd template for docker mode now uses Type=oneshot + RemainAfterExit=yes
so that systemctl is-active returns active when the container is running.
Previously docker run -d exited immediately, causing systemd to mark the
service as inactive even though the container was still up.
- grm list now tries multiple container name fallbacks for docker mode:
1. gitea-runner-{name} (current naming)
2. gitea-runner-{host} (legacy installs where name defaulted to host)
3. systemctl is-active gitea-runner@{name} (for installs with fixed template)
- All tests pass, 100% coverage, ruff + pyright clean