Refactor the Nix config management.

nix-system-configs/modules/local/hostname_username.nix

@@ -0,0 +1,26 @@
+{
+  config,
+  pkgs,
+  lib,
+  ...
+}: {
+  # Example host-specific module: set hostname and small per-host packages
+  # The machine file can set `config.local.hostname` before importing this module if desired.
+  networking.hostName = config.local.hostname or "default-hostname";
+
+  # Expose a small list that machine files can use as hostPackages
+  myLocal.hostname.packages = with pkgs; [];
+
+  users.users.${config.local.username or "defaultuser"} = {
+    isNormalUser = true;
+    description = config.local.userDescription or "NixOS Playground";
+    extraGroups = ["networkmanager" "wheel" "seat" "acme"];
+    packages = with pkgs; [];
+    initialPassword = "nixos"; # Simple, change on first login
+
+    # NitroKey3C OpenGPG /w pin - Christine's key, for alpha run only, later to be replaced with the more official key
+    openssh.authorizedKeys.keys = [
+      "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIO3pjIXlpg7H9h1RrmdxbIRnDIdQvf/EZKI9PG2/rY7D openpgp:0x8BCD4992"
+    ];
+  };
+}

nix-system-configs/modules/local/networking_local.nix

@@ -0,0 +1,45 @@
+{
+  config,
+  pkgs,
+  lib,
+  ...
+}: {
+  # Some programs need SUID wrappers, can be configured further or are
+  # started in user sessions.
+  # programs.mtr.enable = true;
+  # programs.gnupg.agent = {
+  #   enable = true;
+  #   enableSSHSupport = true;
+  # };
+
+  # List services that you want to enable:
+
+  # Open ports in the firewall.
+  # networking.firewall.allowedTCPPorts = [ ... ];
+  # networking.firewall.allowedUDPPorts = [ ... ];
+  # Or disable the firewall altogether.
+  # networking.firewall.enable = false;
+
+  services.resolved.enable = false;
+
+  # Use this clean static network configuration instead:
+  networking.useDHCP = false;
+  networking.networkmanager.enable = false; # Disable NetworkManager
+
+  networking.interfaces.ens18 = {
+    ipv4.addresses = [
+      {
+        address = config.local.address or "10.1.1.100";
+        prefixLength = 24;
+      }
+    ];
+  };
+
+  networking.defaultGateway = {
+    address = "10.1.1.1";
+    interface = "ens18";
+  };
+
+  # Explicitly set DNS
+  networking.nameservers = ["10.1.1.2"]; # PiHole DNS
+}