refactor: move nix settings to system module, remove unused modules

common/system/default.nix

@@ -0,0 +1,27 @@
+{
+  config,
+  pkgs,
+  ...
+}: {
+  nix.gc = {
+    automatic = true;
+    options = "--delete-older-than 30d";
+  };
+  nix.optimise.automatic = true;
+  nix.settings = {
+    extra-experimental-features = [
+      "flakes"
+      "nix-command"
+    ];
+    keep-outputs = true;
+    log-lines = 25;
+    tarball-ttl = 43200;
+    trusted-users = [
+      "root"
+      config.my.user
+    ];
+  };
+  nix.package = pkgs.nix;
+  programs.zsh.enable = true;
+  time.timeZone = "America/New_York";
+}

flakes/nixos.nix

@@ -51,15 +51,9 @@ in {
       }
     ];
 
-    baseHomeModule = {
-      home-manager.useGlobalPkgs = true;
-      home-manager.useUserPackages = true;
-      home-manager.extraSpecialArgs = {inherit inputs;};
-    };
     fullNixOSModules =
       defaultModules
       ++ [
-        baseHomeModule
         {
           home-manager.users.michael = import ../user/environments/nixos/home.nix;
         }
@@ -102,8 +96,6 @@ in {
       modules =
         defaultModules
         ++ [
-          ../modules/nix.nix
-          baseHomeModule
           {
             home-manager.users.michael = import ../user/environments/nixos-server/home.nix;
           }

modules/common.nix

@@ -7,7 +7,6 @@
     ./flatpak.nix
     ./fonts.nix
     ./hosts.nix
-    ./nix.nix
     ./sound.nix
   ];
 }

modules/nix.nix

@@ -1,23 +0,0 @@
-{pkgs, ...}: {
-  nix = {
-    extraOptions = ''
-      experimental-features = flakes nix-command
-    '';
-    # this is required until nix 2.4 is released
-    package = pkgs.nixFlakes;
-
-    settings = {
-      auto-optimise-store = true;
-      trusted-users = ["root" "michael"];
-    };
-    gc = {
-      automatic = true;
-      dates = "weekly";
-      options = "--delete-older-than 30d";
-    };
-  };
-
-  nixpkgs.config = {
-    allowUnfree = true;
-  };
-}