feat: add zsh as default shell

systems/modules/common.nix

@@ -1,4 +1,10 @@
 {pkgs, ...}: {
+  imports = [
+    ./networking.nix
+    ./shell.nix
+    ./stylix.nix
+  ];
+
   users.users.rafiq = {
     isNormalUser = true;
     description = "rafiq";

systems/modules/programs/zsh.nix

@@ -0,0 +1,7 @@
+{pkgs, ...}: {
+  programs.zsh = {
+    enable = true;
+  };
+  users.defaultUserShell = pkgs.zsh;
+  environment.pathsToLink = ["/share/zsh"]; # enables completion
+}

systems/modules/shell.nix

@@ -0,0 +1,5 @@
+{
+  imports = [
+    ./programs/zsh.nix
+  ];
+}

systems/nemesis.nix

@@ -1,12 +1,10 @@
 {
   imports = [
     ./hw-nemesis.nix
-    ./modules/bootloaders/systemd-boot.nix
     ./modules/common.nix
     ./modules/desktop.nix
+    ./modules/bootloaders/systemd-boot.nix
     ./modules/hardware/nvidia.nix
-    ./modules/networking.nix
-    ./modules/stylix.nix
   ];
 
   networking.hostName = "nemesis";

systems/orpheus.nix

@@ -3,8 +3,6 @@
     ./hw-orpheus.nix
     ./modules/bootloaders/extlinux.nix
     ./modules/common.nix
-    ./modules/networking.nix
-    ./modules/stylix.nix
     inputs.nixos-hardware.nixosModules.raspberry-pi-4
     "${inputs.nixpkgs}/nixos/modules/profiles/minimal.nix"
   ];