Add cluster host definitions, cluster utilities, and admin, switch nixpkgs to stable

users/cluster-admin/cluster-admin.nix

@@ -0,0 +1,36 @@
+{ config, pkgs, ... }:
+{
+  users.users.cluster-admin = {
+    initialPassword = "changeme";
+    isNormalUser = true;
+    description = "Cluster Admin";
+    extraGroups = [
+      "networkmanager"
+      "wheel"
+    ];
+  };
+
+  home-manager.users.cluster-admin = {
+    home.username = "cluster-admin";
+    home.homeDirectory = "/home/cluster-admin";
+    home.stateVersion = "25.05";
+
+    home.packages = with pkgs; [ ];
+
+    programs.bash.enable = true;
+
+    programs.git = {
+      enable = true;
+      settings.user = {
+        name = "Corwin Perren";
+        email = "caperren@gmail.com";
+      };
+
+    };
+
+    programs.kitty = {
+      enable = true;
+      font.name = "JetBrains Mono";
+    };
+  };
+}