Add guildhall

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

services/nginx.nix

@@ -210,6 +210,13 @@ in
             proxy_set_header Remote-User $user;
           '';
         };
+        # Co-op idle game. Players are keyed on Remote-User, so nginx must
+        # always overwrite it with the Authelia identity.
+        "guildhall.nordhammer.it" = lib.recursiveUpdate (protectedProxy 8098) {
+          locations."/".extraConfig = autheliaAuthConfig + ''
+            proxy_set_header Remote-User $user;
+          '';
+        };
 
         # Pelican game panel. Can't turn off its own login (no such option
         # upstream), so Authelia is the outer gate and the Pelican account