refactor(manager): 优化全局空状态、错误图片占位并升级遗留消息语法

- 增加表格与树组件全局空状态 (el-empty) 样式规范
- 补齐视图图片语义化 alt，并添加全局图片加载异常 SVG 占位兜底
- 将砍价/秒杀/自定义面板中的 $Message 兼容语法替换为 ElMessage
- 清理冗余依赖 vuex，将 sass-loader 调整至 devDependencies

manager/src/views/order/after-order/afterSaleOrderDetail.vue

@@ -9,7 +9,7 @@
               <dt>退货商品</dt>
               <dd>
                 <div>
-                  <img :src="afterSaleInfo.goodsImage" style="height: 60px">
+                  <img alt="商品图片" :src="afterSaleInfo.goodsImage" style="height: 60px">
                 </div>
                 <a @click="linkTo(afterSaleInfo.goodsId, afterSaleInfo.skuId)">{{ afterSaleInfo.goodsName }}
                 </a><br>
@@ -59,7 +59,7 @@
               <dd v-if="afterSaleImage == ''">暂无凭证</dd>
               <dd v-else>
                 <div class="div-img" v-for="(item, index) in afterSaleImage" :key="index">
-                  <img class="complain-img" :src="item" />
+                  <img alt="投诉凭证" class="complain-img" :src="item" />
                 </div>
               </dd>
             </dl>

manager/src/views/order/order/orderDetail.vue

@@ -195,7 +195,7 @@
             <template #default="{ row }">
               <div v-if="row" style="margin-top: 5px; height: 80px; display: flex">
                 <div>
-                  <img :src="row.image" style="height: 60px; margin-top: 1px; width: 60px" />
+                  <img alt="商品图片" :src="row.image" style="height: 60px; margin-top: 1px; width: 60px" />
                 </div>
                 <div style="margin-left: 13px">
                   <div class="div-zoom">