Initial Ansible automation for hobbs.farm infrastructure

Complete IaC covering:
- 14 roles: common, docker, traefik, vaultwarden, monitoring, media, matrix,
  home_assistant, frigate, adguard, gitea, semaphore, openclaw, security, backup
- Inventory for all hosts (Peggy, Bart, Yoda, NAS, Firewalla)
- Stack playbooks: core-infrastructure, monitoring, media, communication,
  automation, smarthome, security-hardening
- Maintenance playbooks: update-containers, backup, health-check
- Production Docker Compose templates with Traefik labels
- Security hardening (sysctl, auditd, UFW, fail2ban)
- Automated backups with retention policy

roles/monitoring/defaults/main.yml

@@ -0,0 +1,18 @@
+---
+monitoring_compose_dir: "{{ docker_compose_base }}/monitoring"
+prometheus_data_dir: /data/prometheus
+grafana_data_dir: /data/grafana
+alertmanager_data_dir: /data/alertmanager
+
+prometheus_image: "prom/prometheus:latest"
+grafana_image: "grafana/grafana:latest"
+alertmanager_image: "prom/alertmanager:latest"
+node_exporter_image: "prom/node-exporter:latest"
+cadvisor_image: "gcr.io/cadvisor/cadvisor:latest"
+
+prometheus_retention: 30d
+prometheus_scrape_interval: 15s
+grafana_admin_password: "{{ vault_grafana_admin_password }}"
+grafana_host: "grafana.{{ domain }}"
+prometheus_host: "prometheus.{{ domain }}"
+alertmanager_host: "alertmanager.{{ domain }}"