yubikey: add u2f for sudo

system/desktop/yubikey.nix

@@ -2,6 +2,7 @@
 # * https://github.com/drduh/YubiKey-Guide
 # * https://nixos.wiki/wiki/Yubikey
 { pkgs, ... }: {
+
   services.pcscd.enable = true;
   services.udev.packages = [
 
@@ -46,4 +47,8 @@
     };
   };
 
+  # use for pam (sudo)
+  # --------------------------
+  security.pam.u2f.enable = true;
+  security.pam.u2f.authFile = toString <desktop_secrets/yubikey/u2fAuthFile>;
 }