fix: 移动端隐藏标题和logo

frontend/src/App.vue

@@ -6,7 +6,7 @@
         <el-button type="primary" link @click="toggleSidebar">
           <el-icon :size="24"><Fold /></el-icon>
         </el-button>
-        <span class="mobile-title">投标信息一览</span>
+        <span v-if="!isMobile" class="mobile-title">投标信息一览</span>
         <el-button type="primary" link @click="handleLogout" v-if="currentUser">
           <el-icon :size="24"><SwitchButton /></el-icon>
         </el-button>
@@ -18,7 +18,7 @@
 
     <!-- 侧边栏 - 桌面端固定显示，移动端可滑动 -->
     <el-aside :class="{ 'mobile-sidebar': isMobile, 'sidebar-visible': sidebarVisible }" width="200px">
-      <div class="logo">投标信息一览</div>
+      <div v-if="!isMobile" class="logo">投标信息一览</div>
       <el-menu
         active-text-color="#ffd04b"
         background-color="#545c64"