Track LXC container configs and fix network-interfaces

- proxmox/lxc/103.conf: Pi-hole LXC (firewall=0 to fix NAT via fwbr)
- proxmox/lxc/104.conf: Traefik LXC
- proxmox/network-interfaces: Proxmox network config with DNAT/MASQUERADE
  rules; fixes tpost-up typo so DNS DNAT persists across reboots

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

proxmox/lxc/104.conf

@@ -0,0 +1,14 @@
+arch: amd64
+cores: 1
+hostname: traefik
+memory: 256
+nameserver: 10.10.1.2
+net0: name=eth0,bridge=vmbr1,firewall=1,gw=10.10.1.1,hwaddr=BC:24:11:8E:D3:36,ip=10.10.1.3/24,type=veth
+onboot: 1
+ostype: debian
+rootfs: local-zfs:subvol-104-disk-0,size=2G
+swap: 0
+unprivileged: 1
+
+[pve:pending]
+nameserver: 8.8.8.8