feat: 表格区域独立滚动，表头固定

- 修改 common.less：
  - 新增 .page-wrapper 类，使用 flex 纵向布局占满父容器
  - 修改 .table-container 为 flex 布局，让表格自适应高度
  - .el-table 使用 flex:1 实现内容区域滚动、表头固定

- 7个列表页面添加 page-wrapper 类：
  - SystemUser.vue, SystemRole.vue
  - Hitokoto.vue, PhotoWall.vue, Music.vue, SourceImage.vue
  - Article.vue（特殊处理：左右分栏布局适配）

现在设置 100 条数据时，表格内容独立滚动，分页始终可见，不会触发整页滚动。

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/views/api/Hitokoto.vue

@@ -1,5 +1,5 @@
 <template>
-<div>
+<div class="page-wrapper">
   <el-form inline :model="search">
     <el-form-item label="内容">
       <el-input v-model="search.content" />

src/views/api/Music.vue

@@ -1,5 +1,5 @@
 <template>
-<div>
+<div class="page-wrapper">
   <el-form inline :model="search">
     <el-form-item label="名称">
       <el-input v-model="search.name" />

src/views/api/PhotoWall.vue

@@ -1,5 +1,5 @@
 <template>
-<div>
+<div class="page-wrapper">
   <el-alert type="info" show-icon :closable="false" style="margin-bottom: 10px" >
     <template #title>上传要求</template>
     图片格式为{{allowUploadExt.join('、')}}，文件大小不超过10MB。

src/views/api/SourceImage.vue

@@ -1,5 +1,5 @@
 <template>
-<div>
+<div class="page-wrapper">
   <el-alert type="info" show-icon :closable="false" >
     <template #title>上传要求</template>
     图片格式为{{allowUploadExt.join('、')}}，文件大小不超过10MB。

src/views/system/Article.vue

@@ -1,5 +1,5 @@
 <template>
-<div>
+<div class="page-wrapper">
   <div class="search-panel">
   <el-form inline :model="search">
     <el-form-item label="标题">
@@ -52,13 +52,13 @@
       <el-button @click="reset" icon="RefreshLeft">重置</el-button>
     </div>
   </div>
-  <el-row>
-    <el-col :span="4" style="height: 520px;overflow: auto;">
+  <el-row style="flex: 1; overflow: hidden;">
+    <el-col :span="4" style="height: 100%; overflow: auto;">
       <el-tree :props="treeProps" :load="loadTreeData" lazy highlight-current @node-click="articlePreview" />
     </el-col>
-    <el-col :span="20">
-      <div class="table-container">
-      <el-table :data="articleData" v-loading="loading" stripe @selection-change="dataSelect">
+    <el-col :span="20" style="height: 100%; display: flex; flex-direction: column;">
+      <div class="table-container" style="margin-bottom: 0;">
+      <el-table :data="articleData" v-loading="loading" stripe @selection-change="dataSelect" height="100%">
         <el-table-column type="selection" width="55" />
         <el-table-column prop="title" label="标题" />
         <el-table-column prop="path" label="路径" >
@@ -91,8 +91,8 @@
           </template>
         </el-table-column>
       </el-table>
-      <div class="page-container">
-        <el-pagination background 
+      <div class="page-container" style="margin-top: 12px; padding: 0;">
+        <el-pagination background
           :page-sizes="store.state.pageSizeOpts"
           :layout="store.state.pageLayout"
           :current-page="search.pageNum"

src/views/system/SystemRole.vue

@@ -1,5 +1,5 @@
 <template>
-  <div>
+  <div class="page-wrapper">
     <el-form inline :model="search" @submit.prevent>
       <el-form-item label="角色名称/描述">
         <el-input v-model="search.name" />

src/views/system/SystemUser.vue

@@ -1,5 +1,5 @@
 <template>
-<div>
+<div class="page-wrapper">
   <el-form inline :model="search" @submit.prevent>
     <el-form-item label="用户名/昵称">
       <el-input v-model="search.username" />
@@ -35,7 +35,7 @@
     </el-table>
   </div>
   <div class="page-container">
-    <el-pagination background 
+    <el-pagination background
       :page-sizes="store.state.pageSizeOpts"
       :layout="store.state.pageLayout"
       :current-page="search.pageNum"