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/pihole/handlers/main.yml

@@ -0,0 +1,10 @@
+---
+- name: Restart pihole-FTL
+  ansible.builtin.service:
+    name: pihole-FTL
+    state: restarted
+
+- name: Update pihole hosts
+  ansible.builtin.command:
+    cmd: python3 /tmp/pihole_update_hosts.py
+  notify: Restart pihole-FTL