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/103.conf

@@ -0,0 +1,12 @@
+arch: amd64
+cores: 1
+features: nesting=1
+hostname: pihole
+memory: 512
+nameserver: 8.8.8.8
+net0: name=eth0,bridge=vmbr1,firewall=0,gw=10.10.1.1,hwaddr=BC:24:11:D6:DD:FF,ip=10.10.1.2/24,type=veth
+onboot: 1
+ostype: debian
+rootfs: local-zfs:subvol-103-disk-0,size=4G
+swap: 0
+unprivileged: 1