nixos/programs/cardboard-wm: remove

It has a nixpkgs module now so it's fine to remove this.

modules/nixos/default.nix

@@ -1,7 +1,6 @@
 {
   imports = [
     ./programs/blender.nix
-    ./programs/cardboard-wm.nix
     ./programs/distrobox.nix
     ./programs/gnome-session
     ./programs/pop-launcher.nix

modules/nixos/programs/cardboard-wm.nix

@@ -1,56 +0,0 @@
-{ config, lib, pkgs, ... }:
-
-let
-  cfg = config.programs.cardboard-wm;
-
-  cardboardPackage = cfg.package.overrideAttrs (super: rec {
-    passthru.providedSessions = [ "cardboard" ];
-  });
-in
-{
-  options.programs.cardboard-wm = {
-    enable =
-      lib.mkEnableOption "Cardboard, a scrollable tiling Wayland compositor";
-
-    package = lib.mkOption {
-      type = lib.types.package;
-      default = pkgs.cardboard;
-      defaultText = lib.literalExpression "pkgs.cardboard";
-      description = ''
-        The derivation containing the {command}`cardboard` and
-        {command}`cutter` binary.
-      '';
-    };
-
-    extraOptions = lib.mkOption {
-      type = with lib.types; listOf str;
-      default = [ ];
-      description = "Command-line arguments to be passed to Cardboard.";
-    };
-
-    extraPackages = lib.mkOption {
-      type = with lib.types; listOf package;
-      default = [ ];
-      description = ''
-        Extra packages to be installed with this program.
-      '';
-      example = lib.literalExpression ''
-        with pkgs; [
-          waybar
-          eww
-        ]
-      '';
-    };
-  };
-
-  config = lib.mkIf cfg.enable {
-    environment.systemPackages = [ cardboardPackage ] ++ cfg.extraPackages;
-    security.polkit.enable = true;
-    services.xserver.displayManager.sessionPackages = [ cardboardPackage ];
-    hardware.opengl.enable = true;
-    programs.xwayland.enable = true;
-    programs.dconf.enable = true;
-    fonts.enableDefaultFonts = true;
-    xdg.portal.wlr.enable = true;
-  };
-}