feat(jmri): headless JMRI server with Leviton layout power monitor and X11 GUI mode

- Stable udev device symlinks (/dev/jmri/nce, /dev/jmri/loconet, /dev/jmri/lcc)
- jmri-monitor: polls Leviton Decora Smart switch to start/stop JMRI automatically
  - Quiet hours 1-10 AM (no polling)
  - 30s off-delay before shutdown
- LCRR config cloned from Gitea (ssh://gitea.mk-labs.cloud:2221/rblundon/LCRR.git)
- ~/.jmri symlinked to LCRR repo for GitOps config management
- jmri-gui: X11 remote GUI access (PanelPro/DecoderPro) via ssh -X as jmri user
  - Stops daemon, launches GUI, restarts daemon on exit if layout still on
- jmri user gets login shell + SSH key for GUI sessions
- Full JRE installed (openjdk-21-jre) for AWT/X11 support

ansible/host_vars/main-street-station/vars.yml

@@ -0,0 +1,7 @@
+---
+# main-street-station — JMRI / LCRR server
+jmri_profile_id: "My_JMRI_Railroad.3f178885"
+jmri_lcrr_repo: "ssh://git@gitea.mk-labs.cloud:2221/rblundon/LCRR.git"
+jmri_leviton_email: "{{ leviton_email }}"
+jmri_leviton_password: "{{ leviton_password }}"
+jmri_ssh_authorized_key: "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAINnSM/9fO8rz/amqkyoGUzUKNNzzmtSXPwOCr1O9zKNO ansible"