fix Nightly Documentation

.github/latex-manual/manual-template.tex

@@ -21,6 +21,9 @@ $endif$
 %% ─── Page layout ──────────────────────────────────────────────────────────
 \usepackage[a4paper, top=2.5cm, bottom=2.5cm, left=2.5cm, right=2.5cm]{geometry}
 
+%% ─── Text decorations (strikethrough via ~~...~~ in Markdown → \st{}) ────
+\usepackage{soul}
+
 %% ─── Colors ───────────────────────────────────────────────────────────────
 \usepackage[dvipsnames,svgnames,x11names]{xcolor}
 \definecolor{brand-green}{RGB}{7,166,54}