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

inventory/group_vars/docker_hosts.yml

@@ -0,0 +1,9 @@
+---
+docker_compose_base: /data/docker-compose
+docker_data_dir: /data
+docker_log_driver: json-file
+docker_log_max_size: 10m
+docker_log_max_file: "3"
+docker_install_compose_plugin: true
+docker_users:
+  - glyptic