fix(listings): 手机轮播改为居中裁切，左右滑只切换图片

超宽海报在图内横滑不好看。轮播和预览都只保留中间一段，左右滑动回到切换下一张。

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/features/listings/views/MobileHomeView.vue

@@ -103,10 +103,8 @@ const displayBanners = computed<HomeBannerSlide[]>(() => {
   }
   return bannerSlides.value
 })
-const bannerSwipeRef = ref<{ prev: () => void; next: () => void } | null>(null)
 const bannerPreviewVisible = ref(false)
 const bannerPreviewIndex = ref(0)
-const bannerPreviewScroller = ref<HTMLElement | null>(null)
 const bannerPreviewImages = computed(() =>
   displayBanners.value
     .map(slide => slide.image_url?.trim() || '')
@@ -520,42 +518,6 @@ function openCooperationFeedback() {
   cooperationFeedbackPreviewVisible.value = true
 }
 
-let posterDragged = false
-
-function centerWideImage(event: Event) {
-  const img = event.target as HTMLImageElement
-  const scroller = img.parentElement
-  if (!scroller) return
-  scroller.scrollLeft = Math.max(0, (scroller.scrollWidth - scroller.clientWidth) / 2)
-}
-
-function onPosterTouchStart() {
-  posterDragged = false
-}
-
-function onPosterTouchMove() {
-  posterDragged = true
-}
-
-function onPosterClick(slide: HomeBannerSlide) {
-  if (posterDragged) {
-    posterDragged = false
-    return
-  }
-  openBannerPreview(slide)
-}
-
-function stepBanner(step: number) {
-  if (step < 0) bannerSwipeRef.value?.prev()
-  else bannerSwipeRef.value?.next()
-}
-
-function centerBannerPreview() {
-  const scroller = bannerPreviewScroller.value
-  if (!scroller) return
-  scroller.scrollLeft = Math.max(0, (scroller.scrollWidth - scroller.clientWidth) / 2)
-}
-
 function openBannerPreview(slide: HomeBannerSlide) {
   const url = slide.image_url?.trim()
   if (!url) return
@@ -575,11 +537,8 @@ function shiftBannerPreview(step: number) {
   bannerPreviewIndex.value = (bannerPreviewIndex.value + step + total) % total
 }
 
-watch([bannerPreviewVisible, bannerPreviewIndex], async ([open]) => {
+watch(bannerPreviewVisible, open => {
   document.body.style.overflow = open ? 'hidden' : ''
-  if (!open) return
-  await nextTick()
-  centerBannerPreview()
 })
 
 function hasBannerCopy(slide: HomeBannerSlide) {
@@ -973,7 +932,6 @@ if (!restoreHomeConfigFromCache()) {
 
           <!-- Banner 轮播 -->
           <van-swipe
-            ref="bannerSwipeRef"
             class="banner-swipe"
             :class="{
               'is-poster': displayBanners.some(slide => slide.image_url && !hasBannerCopy(slide)),
@@ -995,22 +953,8 @@ if (!restoreHomeConfigFromCache()) {
                 ]"
                 @click="openBannerPreview(slide)"
               >
-                <div
-                  v-if="slide.image_url && !hasBannerCopy(slide)"
-                  class="poster-scroller"
-                  @touchstart.stop="onPosterTouchStart"
-                  @touchmove.stop="onPosterTouchMove"
-                  @click.stop="onPosterClick(slide)"
-                >
-                  <img
-                    class="banner-image"
-                    :src="slide.image_url"
-                    :alt="slide.title || '首页轮播图'"
-                    @load="centerWideImage"
-                  />
-                </div>
                 <img
-                  v-else-if="slide.image_url"
+                  v-if="slide.image_url"
                   class="banner-image"
                   :src="slide.image_url"
                   :alt="slide.title || slide.eyebrow || '首页轮播图'"
@@ -1024,16 +968,6 @@ if (!restoreHomeConfigFromCache()) {
               </div>
             </van-swipe-item>
           </van-swipe>
-          <div
-            v-if="
-              displayBanners.length > 1 &&
-              displayBanners.some(slide => slide.image_url && !hasBannerCopy(slide))
-            "
-            class="banner-step-row"
-          >
-            <button type="button" @click="stepBanner(-1)">上一张</button>
-            <button type="button" @click="stepBanner(1)">下一张</button>
-          </div>
 
           <div class="biz-entry-grid" aria-label="业务入口">
             <RouterLink class="biz-entry" to="/">
@@ -1388,14 +1322,9 @@ if (!restoreHomeConfigFromCache()) {
         <p class="banner-lightbox-count">
           {{ bannerPreviewIndex + 1 }}/{{ bannerPreviewImages.length }}
         </p>
-        <div ref="bannerPreviewScroller" class="banner-lightbox-scroller">
-          <img
-            :src="bannerPreviewImages[bannerPreviewIndex]"
-            alt="轮播图预览"
-            @load="centerBannerPreview"
-          />
+        <div class="banner-lightbox-frame">
+          <img :src="bannerPreviewImages[bannerPreviewIndex]" alt="轮播图预览" />
         </div>
-        <p class="banner-lightbox-hint">左右滑动查看完整海报</p>
         <div v-if="bannerPreviewImages.length > 1" class="banner-lightbox-nav">
           <button type="button" @click="shiftBannerPreview(-1)">上一张</button>
           <button type="button" @click="shiftBannerPreview(1)">下一张</button>