refactor(de): move plasma config to separate file

modules/nix-config/de.nix

@@ -1,36 +0,0 @@
-{
-  pkgs,
-  lib,
-  currentSystemDe,
-  ...
-}:
-let
-  libDe = import ../../lib/libde.nix {
-    inherit currentSystemDe lib;
-  };
-in
-{
-  services = {
-    xserver.enable = true;
-    xserver.excludePackages = with pkgs; [
-      xterm
-    ];
-
-    # Display managers
-    displayManager = {
-      sddm = libDe.ifPlasma {
-        enable = true;
-        wayland.enable = true;
-      };
-    };
-
-    # Desktop environments
-    desktopManager = {
-      plasma6.enable = libDe.ifPlasma true;
-    };
-  };
-  environment.plasma6.excludePackages = with pkgs.kdePackages; [
-    elisa
-    konsole
-  ];
-}

modules/nix-config/default.nix

@@ -16,7 +16,6 @@
   ++ (
     if (currentSystemDe != "none") then
       [
-        ./de.nix
         ./fonts.nix
         ./sound.nix
       ]

modules/nix-config/services.nix

@@ -1,7 +1,11 @@
-{ ... }:
+{ pkgs, ... }:
 {
   services = {
     pcscd.enable = true;
+    xserver.enable = true;
+    xserver.excludePackages = with pkgs; [
+      xterm
+    ];
     openssh = {
       enable = true;
       hostKeys = [