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/routes.yml.j2

@@ -0,0 +1,17 @@
+http:
+  routers:
+{% for svc in traefik_services %}
+    {{ svc.name }}:
+      rule: "Host(`{{ svc.host }}`)"
+      service: {{ svc.name }}
+      entryPoints:
+        - web
+{% endfor %}
+
+  services:
+{% for svc in traefik_services %}
+    {{ svc.name }}:
+      loadBalancer:
+        servers:
+          - url: "{{ svc.backend }}"
+{% endfor %}