feat(nixos): Set default user shell to fish

modules/nixos/programs/fish/default.nix

@@ -0,0 +1,21 @@
+{
+  lib,
+  config,
+  pkgs,
+  ...
+}: let
+  inherit (lib) mkEnableOption mkIf;
+
+  cfg = config.marleyos.programs.fish;
+in {
+  options.marleyos.programs.fish.enable = mkEnableOption "fish";
+
+  config = mkIf cfg.enable {
+    programs.fish = {
+      enable = true;
+      useBabelfish = true;
+    };
+
+    users.defaultUserShell = pkgs.fish;
+  };
+}

systems/x86_64-linux/nyx/default.nix

@@ -36,6 +36,10 @@ in {
 
     wayland.hyprland = enabled;
 
+    programs = {
+      fish = enabled;
+    };
+
     services = {
       ly = enabled;
     };