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/templates/prometheus.yml.j2

@@ -0,0 +1,37 @@
+global:
+  scrape_interval: {{ prometheus_scrape_interval }}
+  evaluation_interval: {{ prometheus_scrape_interval }}
+
+alerting:
+  alertmanagers:
+    - static_configs:
+        - targets:
+            - alertmanager:9093
+
+scrape_configs:
+  - job_name: prometheus
+    static_configs:
+      - targets: ["localhost:9090"]
+
+  - job_name: node-exporter
+    static_configs:
+      - targets:
+          - node-exporter:9100
+        labels:
+          instance: peggy
+      - targets:
+          - 192.168.86.181:9100
+        labels:
+          instance: bart
+
+  - job_name: cadvisor
+    static_configs:
+      - targets: ["cadvisor:8080"]
+
+  - job_name: traefik
+    static_configs:
+      - targets: ["traefik:8080"]
+
+  - job_name: adguard
+    static_configs:
+      - targets: ["adguard-exporter:9617"]