ns2: migrate to OpenTofu management

- Remove hosts/template/ (legacy template1) and give each legacy host
  its own hardware-configuration.nix copy
- Recreate ns2 using create-host with template2 base
- Add secondary DNS services (NSD + Unbound resolver)
- Configure Vault policy for shared DNS secrets
- Fix create-host IP uniqueness validator to check CIDR notation
  (prevents false positives from DNS resolver entries)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

hosts/ns2/configuration.nix

@@ -7,23 +7,38 @@
 
 {
   imports = [
-    ../template/hardware-configuration.nix
+    ../template2/hardware-configuration.nix
 
     ../../system
+    ../../common/vm
+
+    # DNS services
     ../../services/ns/secondary-authorative.nix
     ../../services/ns/resolver.nix
-    ../../common/vm
   ];
 
+  # Host metadata
+  homelab.host = {
+    tier = "prod";
+    role = "dns";
+    labels.dns_role = "secondary";
+  };
+
+  # Enable Vault integration
+  vault.enable = true;
+
+  # Enable remote deployment via NATS
+  homelab.deploy.enable = true;
+
   nixpkgs.config.allowUnfree = true;
-  # Use the systemd-boot EFI boot loader.
   boot.loader.grub.enable = true;
-  boot.loader.grub.device = "/dev/sda";
+  boot.loader.grub.device = "/dev/vda";
 
   networking.hostName = "ns2";
   networking.domain = "home.2rjus.net";
   networking.useNetworkd = true;
   networking.useDHCP = false;
+  # Disable resolved - conflicts with Unbound resolver
   services.resolved.enable = false;
   networking.nameservers = [
     "10.69.13.5"
@@ -47,14 +62,7 @@
     "nix-command"
     "flakes"
   ];
-  vault.enable = true;
-  homelab.deploy.enable = true;
-
-  homelab.host = {
-    role = "dns";
-    labels.dns_role = "secondary";
-  };
-
+  nix.settings.tarball-ttl = 0;
   environment.systemPackages = with pkgs; [
     vim
     wget
@@ -67,5 +75,5 @@
   # Or disable the firewall altogether.
   networking.firewall.enable = false;
 
-  system.stateVersion = "23.11"; # Did you read the comment?
-}
+  system.stateVersion = "25.11"; # Did you read the comment?
+}

hosts/ns2/default.nix

@@ -2,4 +2,4 @@
   imports = [
     ./configuration.nix
   ];
-}
+}

hosts/ns2/hardware-configuration.nix

@@ -1,36 +0,0 @@
-{ config, lib, pkgs, modulesPath, ... }:
-
-{
-  imports =
-    [
-      (modulesPath + "/profiles/qemu-guest.nix")
-    ];
-
-  boot.initrd.availableKernelModules = [ "ata_piix" "uhci_hcd" "virtio_pci" "virtio_scsi" "sd_mod" "sr_mod" ];
-  boot.initrd.kernelModules = [ ];
-  # boot.kernelModules = [ ];
-  # boot.extraModulePackages = [ ];
-
-  fileSystems."/" =
-    {
-      device = "/dev/disk/by-uuid/6889aba9-61ed-4687-ab10-e5cf4017ac8d";
-      fsType = "xfs";
-    };
-
-  fileSystems."/boot" =
-    {
-      device = "/dev/disk/by-uuid/BC07-3B7A";
-      fsType = "vfat";
-    };
-
-  swapDevices =
-    [{ device = "/dev/disk/by-uuid/64e5757b-6625-4dd2-aa2a-66ca93444d23"; }];
-
-  # Enables DHCP on each ethernet and wireless interface. In case of scripted networking
-  # (the default) this is the recommended approach. When using systemd-networkd it's
-  # still possible to use this option, but it's recommended to use it in conjunction
-  # with explicit per-interface declarations with `networking.interfaces.<interface>.useDHCP`.
-  # networking.interfaces.ens18.useDHCP = lib.mkDefault true;
-
-  nixpkgs.hostPlatform = lib.mkDefault "x86_64-linux";
-}