feat: 商品详情页图片缩放显示改进

- 添加缩略图列表切换功能
- 点击主图可放大预览
- 添加缩放提示文字
- 优化移动端样式

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

frontend/src/views/user/ProductDetail.vue

@@ -5,26 +5,39 @@
       <el-row :gutter="32">
         <el-col :span="12">
           <div class="product-images">
-            <el-carousel v-if="productImages.length > 1" height="400px" :autoplay="false" indicator-position="outside">
-              <el-carousel-item v-for="(img, index) in productImages" :key="index">
-                <el-image :src="img" fit="contain" class="carousel-image" :preview-src-list="productImages" :initial-index="index">
+            <!-- 主图显示 -->
+            <div class="main-image-wrap">
+              <el-image
+                :src="currentImage"
+                fit="contain"
+                class="main-image"
+                :preview-src-list="productImages"
+                :initial-index="currentImageIndex"
+                :z-index="9999"
+              >
                 <template #error>
                   <div class="image-placeholder">
                     <el-icon size="80"><Goods /></el-icon>
                   </div>
                 </template>
               </el-image>
-              </el-carousel-item>
-            </el-carousel>
-            <el-image v-else-if="productImages.length === 1" :src="productImages[0]" fit="contain" class="single-image" :preview-src-list="productImages">
-              <template #error>
-                <div class="image-placeholder">
-                  <el-icon size="80"><Goods /></el-icon>
             </div>
-              </template>
-            </el-image>
-            <div v-else class="image-placeholder">
-              <el-icon size="80"><Goods /></el-icon>
+            <!-- 缩略图列表 -->
+            <div class="thumbnail-list" v-if="productImages.length > 1">
+              <div
+                v-for="(img, index) in productImages"
+                :key="index"
+                class="thumbnail-item"
+                :class="{ active: currentImageIndex === index }"
+                @click="currentImageIndex = index"
+              >
+                <el-image :src="img" fit="cover" class="thumbnail-image" />
+              </div>
+            </div>
+            <!-- 单图提示 -->
+            <div class="image-tip" v-if="productImages.length > 0">
+              <el-icon><ZoomIn /></el-icon>
+              <span>点击图片放大查看</span>
             </div>
           </div>
         </el-col>
@@ -65,7 +78,7 @@
 import { ref, computed, onMounted } from 'vue'
 import { useRoute, useRouter } from 'vue-router'
 import { ElMessage } from 'element-plus'
-import { Goods } from '@element-plus/icons-vue'
+import { Goods, ZoomIn } from '@element-plus/icons-vue'
 import { productApi, userApi } from '../../api'
 import { useCartStore } from '../../store/cart'
 import { useI18n } from 'vue-i18n'
@@ -79,12 +92,17 @@ const cartStore = useCartStore()
 const product = ref<any>(null)
 const quantity = ref(1)
 const userCredits = ref(0)
+const currentImageIndex = ref(0)
 
 const productImages = computed(() => {
   if (!product.value?.images) return []
   return product.value.images.split(',').map((s: string) => s.trim()).filter(Boolean).map((url: string) => getImageUrl(url))
 })
 
+const currentImage = computed(() => {
+  return productImages.value[currentImageIndex.value] || ''
+})
+
 // 检查用户是否有足够资格购买
 function hasEnoughCredit(): boolean {
   if (!product.value || !product.value.require_credit) return true
@@ -139,17 +157,68 @@ function buyNow() {
 .product-detail-page { padding: 0; }
 .detail-card { background: #2d2d44; border: 1px solid rgba(255, 255, 255, 0.06); border-radius: 12px; padding: 32px; }
 .product-images {
-  height: 400px;
   background: rgba(255, 255, 255, 0.04);
   border-radius: 12px;
   overflow: hidden;
 
-  .carousel-image, .single-image {
-    width: 100%;
+  .main-image-wrap {
     height: 400px;
     display: flex;
     align-items: center;
     justify-content: center;
+    cursor: pointer;
+
+    .main-image {
+      max-width: 100%;
+      max-height: 100%;
+    }
+  }
+
+  .thumbnail-list {
+    display: flex;
+    gap: 8px;
+    padding: 12px;
+    background: rgba(0, 0, 0, 0.2);
+
+    .thumbnail-item {
+      width: 60px;
+      height: 60px;
+      border-radius: 6px;
+      overflow: hidden;
+      cursor: pointer;
+      border: 2px solid transparent;
+      transition: all 0.2s;
+      opacity: 0.6;
+
+      &:hover {
+        opacity: 0.9;
+      }
+
+      &.active {
+        border-color: #4e6ef2;
+        opacity: 1;
+      }
+
+      .thumbnail-image {
+        width: 100%;
+        height: 100%;
+      }
+    }
+  }
+
+  .image-tip {
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    gap: 4px;
+    padding: 8px;
+    background: rgba(0, 0, 0, 0.3);
+    color: rgba(255, 255, 255, 0.5);
+    font-size: 12px;
+
+    .el-icon {
+      font-size: 14px;
+    }
   }
 
   .image-placeholder {
@@ -208,15 +277,16 @@ h1 { font-size: 28px; color: #fff; margin-bottom: 16px; }
   }
 
   .product-images {
+    .main-image-wrap {
       height: 300px;
     }
 
-  .carousel-image, .single-image {
-    height: 300px;
+    .thumbnail-list {
+      .thumbnail-item {
+        width: 50px;
+        height: 50px;
+      }
     }
-
-  .image-placeholder {
-    height: 300px;
   }
 
   h1 {