feat(hosts): add NaroMk3 to the existing hosts

hosts/naromk3/configuration.nix

@@ -0,0 +1,75 @@
+{inputs, ...}: {
+  imports = [
+    ./hardware-configuration.nix
+    inputs.home-manager.nixosModules.default
+    ../../system
+  ];
+
+  mySystem = {
+    boot = {
+      kernel = {
+        hardened = true;
+        cpuVendor = "amd";
+      };
+      grub = {
+        enable = true;
+        device = "/dev/sdb";
+      };
+    };
+    dev.docker.enable = true;
+    misc.keymap = "fr-bepo";
+    networking = {
+      hostname = "NaroMk3";
+      id = "0003beef";
+      firewall = {
+        openPorts = [
+          22 # Gitea SSH
+          80 # HTTP
+          443 # HTTPS
+        ];
+      };
+    };
+    packages.nix = {
+      gc.automatic = true;
+      trusted-users = ["phundrak"];
+    };
+    services = {
+      endlessh.enable = false;
+      ssh = {
+        enable = true;
+        allowedUsers = ["phundrak"];
+        passwordAuthentication = false;
+        port = 2222; # port 22 will be used by Gitea
+      };
+    };
+    users = {
+      root.disablePassword = true;
+      phundrak.enable = true;
+    };
+  };
+
+  # This option defines the first version of NixOS you have installed
+  # on this particular machine, and is used to maintain compatibility
+  # with application data (e.g. databases) created on older NixOS
+  # versions.
+  #
+  # Most users should NEVER change this value after the initial
+  # install, for any reason, even if you've upgraded your system to a
+  # new NixOS release.
+  #
+  # This value does NOT affect the Nixpkgs version your packages and
+  # OS are pulled from, so changing it will NOT upgrade your system -
+  # see https://nixos.org/manual/nixos/stable/#sec-upgrading for how
+  # to actually do that.
+  #
+  # This value being lower than the current NixOS release does NOT
+  # mean your system is out of date, out of support, or vulnerable.
+  #
+  # Do NOT change this value unless you have manually inspected all
+  # the changes it would make to your configuration, and migrated your
+  # data accordingly.
+  #
+  # For more information, see `man configuration.nix` or
+  # https://nixos.org/manual/nixos/stable/options#opt-system.stateVersion
+  system.stateVersion = "25.05"; # Did you read the comment?
+}