add keyboardbindings to desktop module for niri

modules/desktop/default.nix

@@ -100,6 +100,12 @@ in
 
     nitrokey.enable = mkEnableOption "Nitrokey hardware security key support";
 
+    niri.hotkeyVariant = mkOption {
+      type        = types.enum [ "default" "lifebook" ];
+      default     = "default";
+      description = "Niri hotkey variant to deploy — selects binds/<variant>.kdl.";
+    };
+
     git.signingKey = mkOption {
       type        = types.str;
       default     = "/home/${user}/.ssh/id_ed25519_sk_rk_red";
@@ -243,6 +249,9 @@ in
           ../wm/niri/home.nix
         ];
 
+        xdg.configFile."niri/binds.kdl".source =
+          ../wm/niri/binds/${cfg.niri.hotkeyVariant}.kdl;
+
         services = {
           mako.enable         = true;
           polkit-gnome.enable = true;