Update Nix flake, refactor Darwin app aliases and use it for system and

home config. Remove qutebrowser, mousecat, move some apps from brew ->
nixpkgs, add firefox to mac

nix/system/darwin.nix

@@ -1,9 +1,13 @@
 {
   pkgs,
   config,
+  lib,
   self,
   ...
 }:
+let
+  utils = import ../utils.nix;
+in
 {
 
   environment.systemPackages = with pkgs; [
@@ -15,12 +19,9 @@
     enable = true;
     casks = [
       "ghostty"
-      "nikitabobko/tap/aerospace"
-      "qutebrowser"
-      "shortcat"
     ];
     brews = [
-      "mas"
+      "bitwarden-cli"
     ];
     masApps = { };
     onActivation.cleanup = "zap";
@@ -68,25 +69,13 @@
       remapCapsLockToEscape = true;
       swapLeftCtrlAndFn = false;
     };
-    activationScripts.applications.text =
-      let
-        env = pkgs.buildEnv {
-          name = "system-applications";
-          paths = config.environment.systemPackages;
-          pathsToLink = "/Applications";
-        };
-      in
-      pkgs.lib.mkForce ''
-        # Set up applications
-        echo "setting up /Applications..." >&2
-        rm -rf /Applications/Nix\ Apps
-        mkdir -p /Applications/Nix\ Apps
-        find ${env}/Applications -maxdepth 1 -type l -exec readlink '{}' + |
-        while read -r src; do
-          app_name=$(basename "$src")
-          echo "copying $src" >&2
-          ${pkgs.mkalias}/bin/mkalias "$src" "/Applications/Nix Apps/$app_name"
-        done
-      '';
+
+    activationScripts.applications.text = utils.mkAppAliasSystem {
+      derivationName = "system-applications";
+      appsPath = config.environment.systemPackages;
+      outputDir = "/Applications/Nix";
+      pkgs = pkgs;
+      lib = lib;
+    };
   };
 }