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

playbooks/monitoring.yml

@@ -0,0 +1,8 @@
+---
+- name: Deploy monitoring stack
+  hosts: peggy
+  roles:
+    - role: docker
+      tags: [docker]
+    - role: monitoring
+      tags: [monitoring, prometheus, grafana, alertmanager]