Add Pi-hole and Traefik LXC containers

- LXC 103 (pihole): Debian 12, 10.10.1.2, Pi-hole v6 with local DNS for
  gitea/grafana/traefik/pihole.homelab, Proxmox dnsmasq updated to use
  Pi-hole upstream
- LXC 104 (traefik): Debian 12, 10.10.1.3, Traefik v3 routing
  gitea.homelab → 10.10.1.125:3000, grafana.homelab → 10.10.1.137:3000
- DNAT rules on vmbr0 forwarding :80/:443 to Traefik, persisted in
  /etc/network/interfaces
- Ansible roles: pihole, traefik; playbooks: pihole.yml, traefik.yml
- site.yml excludes Debian containers from Arch-specific common role

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ansible/roles/traefik/templates/traefik.yml.j2

@@ -0,0 +1,15 @@
+api:
+  dashboard: true
+  insecure: true
+
+entryPoints:
+  web:
+    address: ":{{ traefik_http_port }}"
+
+providers:
+  file:
+    directory: /etc/traefik/conf.d
+    watch: true
+
+log:
+  level: {{ traefik_log_level }}