From 9a6df6438bbeb2ffc1da844065a4a8ca7512b048 Mon Sep 17 00:00:00 2001
From: CGH0S7 <776459475@qq.com>
Date: Mon, 13 Apr 2026 15:55:43 +0800
Subject: [PATCH] Remove dead chi derivative setup in BSSN RHS

(cherry picked from commit e4e741caa17703386f6e247cf486f2ccbad99ce3)