add gdm as dm for niri.

nixos/modules/gui/niri.nix

@@ -0,0 +1,34 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+let
+  cfg = config.youthlic.gui;
+in
+{
+  config = lib.mkIf (cfg.enabled == "niri") {
+    environment.systemPackages = with pkgs; [
+      bluez
+    ];
+    hardware.bluetooth = {
+      enable = true;
+    };
+    services.xserver = {
+      enable = true;
+      xkb = {
+        layout = "cn";
+        variant = "";
+      };
+      displayManager.gdm = {
+        enable = true;
+        wayland = true;
+      };
+    };
+    programs.niri = {
+      enable = true;
+      package = pkgs.niri-unstable;
+    };
+  };
+}