fix(轮播): 修复新闻轮播切换时的闪烁问题并实现无缝循环

添加过渡状态检测防止快速点击导致的闪烁
实现尾部克隆技术完成无缝循环效果
优化最后一张的显示逻辑和复位处理

@@ -174,7 +174,7 @@
               src="/src/assets/images/02 西园戒幢律寺三坛大戒法会/下@2x.png"
               alt="下一张"
               @click="nextSlide"
-              :class="{ disabled: currentSlide >= maxSlide }"
+              :class="{ disabled: isTransitioning }"
             >
           </div>
         </div>
@@ -342,6 +342,8 @@ const viewMore = (type) => {
 // 新闻轮播相关逻辑
 const newsCarousel = ref(null)
 const currentSlide = ref(0)
+const isTransitioning = ref(false)
+const hasTailClone = ref(false)
 
 // 新闻数据
 const newsItems = ref([
@@ -367,6 +369,9 @@ const newsItems = ref([
   }
 ])
 
+// 原始长度用于判断“最后一张”的逻辑
+const initialLength = ref(newsItems.value.length)
+
 // 计算最大滑动位置
 const maxSlide = computed(() => {
   return Math.max(0, newsItems.value.length - 1)
@@ -376,14 +381,39 @@ const maxSlide = computed(() => {
 const prevSlide = () => {
   if (currentSlide.value > 0) {
     currentSlide.value--
+    // 离开最后一张时移除尾部克隆，避免轨道长度异常
+    if (hasTailClone.value && currentSlide.value < initialLength.value - 1) {
+      newsItems.value.pop()
+      hasTailClone.value = false
+    }
     updateCarouselPosition()
   }
 }
 
 // 下一张
 const nextSlide = () => {
-  if (currentSlide.value < maxSlide.value) {
+  if (isTransitioning.value) return
+
+  // 若还未到原始最后一张，正常前进
+  if (currentSlide.value < initialLength.value - 1) {
     currentSlide.value++
+    // 当抵达原始最后一张时，预先追加尾部克隆以填充右侧空白
+    if (currentSlide.value === initialLength.value - 1 && !hasTailClone.value) {
+      newsItems.value.push(newsItems.value[0])
+      hasTailClone.value = true
+    }
+    isTransitioning.value = true
+    attachTransitionEndOnce(false)
+    updateCarouselPosition()
+  } else {
+    // 处于原始最后一张：使用尾部克隆进行无缝循环
+    if (!hasTailClone.value) {
+      newsItems.value.push(newsItems.value[0])
+      hasTailClone.value = true
+    }
+    currentSlide.value++
+    isTransitioning.value = true
+    attachTransitionEndOnce(true)
     updateCarouselPosition()
   }
 }
@@ -393,29 +423,44 @@ const updateCarouselPosition = () => {
   const carouselEl = newsCarousel.value
   if (!carouselEl) return
 
-  const containerEl = carouselEl.parentElement
-  const containerWidth = containerEl ? containerEl.clientWidth : 0
   const firstItem = carouselEl.querySelector('.news-item')
   if (!firstItem) return
 
   const itemWidth = firstItem.getBoundingClientRect().width
-  // 读取gap像素值，回退到0.5rem（8px）
   let gapStr = getComputedStyle(carouselEl).gap
   if (!gapStr || gapStr === 'normal') {
     gapStr = '8px'
   }
   const gapPx = parseFloat(gapStr) || 8
 
-  let distance = currentSlide.value * (itemWidth + gapPx)
+  const distance = currentSlide.value * (itemWidth + gapPx)
+  carouselEl.style.transform = `translateX(-${distance}px)`
+}
 
-  // 最后一张时，保证完整显示（居中显示，无下一张时不被裁切）
-  if (currentSlide.value === maxSlide.value) {
-    const lastOffset = (newsItems.value.length - 1) * (itemWidth + gapPx)
-    const centerOffset = Math.max(0, (containerWidth - itemWidth) / 2)
-    distance = lastOffset - centerOffset
+// 动画结束后复位（如处于无缝循环场景）
+const attachTransitionEndOnce = (looping) => {
+  const el = newsCarousel.value
+  if (!el) {
+    isTransitioning.value = false
+    return
+  }
+  const handler = () => {
+    el.removeEventListener('transitionend', handler)
+    if (looping) {
+      const prevTransition = el.style.transition
+      el.style.transition = 'none'
+      // 移除临时克隆，重置到第一张
+      newsItems.value.pop()
+      hasTailClone.value = false
+      currentSlide.value = 0
+      updateCarouselPosition()
+      // 强制重绘后恢复过渡
+      void el.offsetHeight
+      el.style.transition = prevTransition || 'transform 0.3s ease'
+    }
+    isTransitioning.value = false
   }
-
-  carouselEl.style.transform = `translateX(-${distance}px)`
+  el.addEventListener('transitionend', handler)
 }
 
 // 处理新闻点击事件