fix: 移动端列表页搜索框和按钮去掉size=small，使用默认大小

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

frontend/src/views/mobile/PlansList.vue

@@ -51,8 +51,8 @@ async function handleDelete(id: string) {
     <button class="new-btn" @click="router.push('/m/work-plan/new')">+ 新建计划</button>
 
         <div style="margin-bottom:12px;display:flex;gap:8px">
-      <el-input v-model="searchText" placeholder="搜索..." size="small" clearable @keyup.enter="onSearch" @clear="onSearch" />
-      <el-button size="small" @click="onSearch">搜索</el-button>
+      <el-input v-model="searchText" placeholder="搜索..." clearable @keyup.enter="onSearch" @clear="onSearch" />
+      <el-button @click="onSearch">搜索</el-button>
     </div>
 
     <div class="cards">