feat(product.js): 相关产品模块不超过4个时。不展示切换按钮。

public/themes/dist_static/static/js/product.js

@@ -32,10 +32,18 @@ function relatedCarouselInit() {
 	const root = document.querySelector(".p-related");
 	const el = root?.querySelector(".p-related__swiper");
 	if (!root || !el || !window.Swiper) return;
+	const slideCount = el.querySelectorAll(".swiper-wrapper > .swiper-slide").length;
+	// 一屏展示 4 条，不超过 4 条时隐藏切换按钮
+	if (slideCount <= 4) {
+		root.querySelectorAll(".p-related__header .s-arrows").forEach((node) => {
+			node.style.display = "none";
+		});
+	}
 	new window.Swiper(el, {
 		slidesPerView: 1.15,
 		spaceBetween: 16,
 		grabCursor: true,
+		watchOverflow: true,
 		pagination: {
 			el: root.querySelector(".p-related__pagination"),
 			clickable: true