♻️ consolidate nix configs

nix/modules/base/darwin.nix

@@ -0,0 +1,57 @@
+{ pkgs, dotfiles, ... }: {
+
+  imports = [ ./common.nix ];
+
+  nix = {
+    configureBuildUsers = true;
+
+    extraOptions = ''
+      extra-platforms = x86_64-darwin aarch64-darwin
+    '';
+
+    gc = {
+      interval = {
+        Hour = 3;
+        Minute = 16;
+        Weekday = 6;
+      };
+      options = "--delete-older-than 30d";
+    };
+    settings = {
+      trusted-users = [ "root" "@admin" ];
+    };
+  };
+
+  environment.etc = {
+    "sudoers.d/walkah".text = ''
+      walkah   ALL = (ALL) NOPASSWD: ALL
+    '';
+  };
+
+  homebrew = {
+    enable = true;
+    brewPrefix = "/opt/homebrew/bin";
+    global = {
+      brewfile = true;
+      lockfiles = false;
+    };
+    onActivation = {
+      autoUpdate = true;
+      cleanup = "zap";
+      upgrade = true;
+    };
+  };
+
+  home-manager = {
+    useGlobalPkgs = true;
+    useUserPackages = true;
+    users.walkah = import "${dotfiles}/home.nix";
+  };
+
+  users.users.walkah = {
+    home = "/Users/walkah";
+    shell = pkgs.zsh;
+  };
+
+  system.stateVersion = 4;
+}