Fix home-manager impurity and add brew configuration

modules/darwin/preferences.nix

@@ -0,0 +1,57 @@
+{ config, pkgs, ... }: {
+
+  system.defaults = {
+    loginwindow = {
+      GuestEnabled = false;
+      SHOWFULLNAME = false;
+    };
+
+    finder = {
+      AppleShowAllExtensions = true;
+      FXEnableExtensionChangeWarning = true;
+      _FXShowPosixPathInTitle = true;
+    };
+
+    trackpad = {
+      ActuationStrength = 0;
+      Clicking = true;
+      FirstClickThreshold = 1;
+      SecondClickThreshold = 1;
+      TrackpadRightClick = false;
+    };
+
+    # firewall
+    alf = {
+      # 0 = disabled 1 = enabled 2 = blocks all connections except for essential services
+      globalstate = 1;
+      loggingenabled = 0;
+      stealthenabled = 1;
+    };
+
+    dock = {
+      autohide = true;
+      autohide-delay = "0.0";
+      autohide-time-modifier = "1.0";
+      tilesize = 50;
+      static-only = false;
+      showhidden = false;
+      show-recents = false;
+      show-process-indicators = true;
+      orientation = "bottom";
+      mru-spaces = false;
+    };
+
+    NSGlobalDomain = {
+      "com.apple.sound.beep.feedback" = 0;
+      "com.apple.sound.beep.volume" = "0.000";
+      ApplePressAndHoldEnabled = false;
+      # delay before repeating keystrokes
+      InitialKeyRepeat = 10;
+      # delay between repeated keystrokes upon holding a key
+      KeyRepeat = 1;
+      AppleShowAllExtensions = true;
+      AppleShowScrollBars = "Automatic";
+    };
+  };
+
+}