shell: chunk up usecases

shell.nix

@@ -7,29 +7,26 @@
         ./nix/packages/overlay.nix
       ];
     },
-}:
+}: rec {
-pkgs.mkShell {
+  default = pkgs.mkShell {
-  name = "dotfiles";
     packages = with pkgs; [
-    #
-    # Just scripts
-    #
       just
       jq
+      npins
+      disko
+    ];
+  };
+
+  withXMonad = pkgs.mkShell {
+    inputsFrom = with pkgs; [
+      default
 
-    #
-    # XMonad
-    #
       (haskellPackages.ghcWithPackages (self: [
         self.xmonad-contrib
         self.xmonad-extras
       ]))
       haskell-language-server
       cabal-install
-
-    #
-    # Installer testing
-    #
-    disko
     ];
+  };
 }