Add public status dashboard at cloud.ladkau.de

Shows live service health (green/red links) and server CPU, RAM, and
disk usage with progress bars. Reads host stats from /host/proc,
checks service endpoints every 30 s, and serves a frosted-glass UI
over a configurable background image (ansible/roles/dashboard/files/bg.jpg).

ansible/roles/dashboard/handlers/main.yml

@@ -0,0 +1,7 @@
+---
+- name: Restart dashboard
+  community.docker.docker_compose_v2:
+    project_src: "{{ dashboard_data_dir }}"
+    state: present
+    pull: missing
+    recreate: always