fix: 调整导航栏显示和图片预览逻辑

- 修改商品动态页面的导航栏显示配置
- 简化图片预览功能，仅显示单张图片
- 移除部分响应式媒体查询样式
- 修复isAdmin变量声明方式

src/App.vue

@@ -36,7 +36,7 @@ onMounted(() => {
   const code = urlParams.get('code') || undefined;
   const state = urlParams.get('state') || undefined;
   const corpid = urlParams.get('corpid') || undefined;
-  const isAdmin = urlParams.get('isAdmin') || undefined;
+  let isAdmin = urlParams.get('isAdmin') || undefined;
 
   if (state && state.indexOf('token') !== -1) {
     const token = state.split('token_')[1];

src/pages/order/borrow-return-dynamic.vue

@@ -77,21 +77,23 @@ function previewCoverImage(imgUrl: string) {
 // 预览归还图片组
 function previewReturnImages(images: string[], startIndex = 0) {
   if (!images || images.length === 0) return
-  showImagePreview({
+  /* showImagePreview({
     images,
     startPosition: startIndex,
     closeable: true
-  })
+  }) */
+ showImagePreview([images[startIndex]]);
 }
 
 // 预览审批图片组
 function previewAuditImages(images: string[], startIndex = 0) {
   if (!images || images.length === 0) return
-  showImagePreview({
+  /* showImagePreview({
     images,
     startPosition: startIndex,
     closeable: true
-  })
+  }) */
+ showImagePreview([images[startIndex]]);
 }
 
 // 初始化加载
@@ -316,7 +318,7 @@ onMounted(() => {
 
 .timeline-dot {
   position: absolute;
-  left: -32px;
+  left: -30px;
   top: 0;
   display: flex;
   flex-direction: column;
@@ -667,7 +669,7 @@ onMounted(() => {
 }
 
 /* 响应式调整 */
-@media (max-width: 400px) {
+/* @media (max-width: 400px) {
   .borrow-return-dynamic-page {
     padding: 12px;
   }
@@ -704,7 +706,7 @@ onMounted(() => {
     gap: 8px;
   }
 }
-
+ */
 /* 动画效果 */
 @keyframes fadeIn {
   from {
@@ -722,7 +724,7 @@ onMounted(() => {
 }
 
 /* 大屏幕优化 */
-@media (min-width: 768px) {
+/* @media (min-width: 768px) {
   .borrow-return-dynamic-page {
     max-width: 800px;
     margin: 0 auto;
@@ -732,7 +734,7 @@ onMounted(() => {
   .dynamic-card {
     border-radius: 16px;
   }
-}
+} */
 
 /* 美化分隔线 */
 .van-divider {

src/router/index.ts

@@ -90,8 +90,8 @@ export const routes: RouteRecordRaw[] = [
       title: "商品动态",
       layout: {
         navBar: {
-          showNavBar: true,
-          showLeftArrow: true
+          showNavBar: false,
+          showLeftArrow: false
         },
         tabbar: {
           showTabbar: true,