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/templates/docker-compose.yml.j2

@@ -0,0 +1,29 @@
+# Managed by Ansible — do not edit manually
+services:
+  dashboard:
+    image: python:3.12-alpine
+    container_name: dashboard
+    command: python /app/app.py
+    restart: unless-stopped
+    volumes:
+      - {{ dashboard_data_dir }}/app.py:/app/app.py:ro
+      - {{ dashboard_data_dir }}/bg.jpg:/app/bg.jpg:ro
+      # Host proc/sys for CPU and RAM stats
+      - /proc:/host/proc:ro
+      # Host root filesystem (read-only) for disk stats
+      - /:/host:ro
+    networks:
+      - traefik_public
+    labels:
+      - "traefik.enable=true"
+      # Catch all traffic to cloud.ladkau.de not matched by the more specific
+      # Traefik dashboard router (which has PathPrefix /dashboard and /api)
+      - "traefik.http.routers.status.rule=Host(`{{ domain_cloud }}`)"
+      - "traefik.http.routers.status.entrypoints=websecure"
+      - "traefik.http.routers.status.tls.certresolver=letsencrypt"
+      - "traefik.http.services.status.loadbalancer.server.port=8080"
+      - "traefik.http.routers.status.middlewares=rate-limit@docker"
+
+networks:
+  traefik_public:
+    external: true