refactor(frontend): 将备份和数据管理页面合并为设置页的标签页

将独立的 /admin/backup 和 /admin/data-management 页面整合到设置页，
作为「备份」和「Sora 存储」标签页，减少侧边栏条目，集中管理配置。

- 移除 BackupView 和 DataManagementView 的 AppLayout 包装
- 在 SettingsView 中以子组件形式嵌入，使用 v-show 切换标签
- 删除独立路由和侧边栏菜单入口
- 备份/数据标签页下隐藏主保存按钮（各自有独立保存）
- 优化标签栏样式适配7个标签，PC端支持细滚动条
- 清理未使用的图标组件和 i18n 键

frontend/src/views/admin/BackupView.vue

@@ -1,5 +1,4 @@
 <template>
-  <AppLayout>
     <div class="space-y-6">
       <!-- S3 Storage Config -->
       <div class="card p-6">
@@ -275,13 +274,11 @@
         </div>
       </transition>
     </teleport>
-  </AppLayout>
 </template>
 
 <script setup lang="ts">
 import { computed, onMounted, ref } from 'vue'
 import { useI18n } from 'vue-i18n'
-import AppLayout from '@/components/layout/AppLayout.vue'
 import { adminAPI } from '@/api'
 import { useAppStore } from '@/stores'
 import type { BackupS3Config, BackupScheduleConfig, BackupRecord } from '@/api/admin/backup'

frontend/src/views/admin/DataManagementView.vue

@@ -1,5 +1,4 @@
 <template>
-  <AppLayout>
     <div class="space-y-6">
       <div class="card p-6">
         <div class="mb-4 flex flex-wrap items-center justify-between gap-3">
@@ -183,13 +182,11 @@
         </div>
       </Transition>
     </Teleport>
-  </AppLayout>
 </template>
 
 <script setup lang="ts">
 import { onMounted, ref } from 'vue'
 import { useI18n } from 'vue-i18n'
-import AppLayout from '@/components/layout/AppLayout.vue'
 import type { SoraS3Profile } from '@/api/admin/settings'
 import { adminAPI } from '@/api'
 import { useAppStore } from '@/stores'

frontend/src/views/admin/SettingsView.vue

@@ -9,7 +9,7 @@
       <!-- Settings Form -->
       <form v-else @submit.prevent="saveSettings" class="space-y-6">
         <!-- Tab Navigation -->
-        <div class="sticky top-0 z-10 overflow-x-auto scrollbar-hide">
+        <div class="sticky top-0 z-10 overflow-x-auto settings-tabs-scroll">
           <nav class="settings-tabs">
             <button
               v-for="tab in settingsTabs"
@@ -1649,8 +1649,18 @@
         </div>
         </div><!-- /Tab: Email -->
 
+        <!-- Tab: Backup -->
+        <div v-show="activeTab === 'backup'">
+          <BackupSettings />
+        </div>
+
+        <!-- Tab: Data Management -->
+        <div v-show="activeTab === 'data'">
+          <DataManagementSettings />
+        </div>
+
         <!-- Save Button -->
-        <div class="flex justify-end">
+        <div v-show="activeTab !== 'backup' && activeTab !== 'data'" class="flex justify-end">
           <button type="submit" :disabled="saving" class="btn btn-primary">
             <svg v-if="saving" class="h-4 w-4 animate-spin" fill="none" viewBox="0 0 24 24">
               <circle
@@ -1692,6 +1702,8 @@ import GroupBadge from '@/components/common/GroupBadge.vue'
 import GroupOptionItem from '@/components/common/GroupOptionItem.vue'
 import Toggle from '@/components/common/Toggle.vue'
 import ImageUpload from '@/components/common/ImageUpload.vue'
+import BackupSettings from '@/views/admin/BackupView.vue'
+import DataManagementSettings from '@/views/admin/DataManagementView.vue'
 import { useClipboard } from '@/composables/useClipboard'
 import { useAppStore } from '@/stores'
 import { useAdminSettingsStore } from '@/stores/adminSettings'
@@ -1706,7 +1718,7 @@ const { t } = useI18n()
 const appStore = useAppStore()
 const adminSettingsStore = useAdminSettingsStore()
 
-type SettingsTab = 'general' | 'security' | 'users' | 'gateway' | 'email'
+type SettingsTab = 'general' | 'security' | 'users' | 'gateway' | 'email' | 'backup' | 'data'
 const activeTab = ref<SettingsTab>('general')
 const settingsTabs = [
   { key: 'general'  as SettingsTab, icon: 'home'   as const },
@@ -1714,6 +1726,8 @@ const settingsTabs = [
   { key: 'users'    as SettingsTab, icon: 'user'   as const },
   { key: 'gateway'  as SettingsTab, icon: 'server' as const },
   { key: 'email'    as SettingsTab, icon: 'mail'   as const },
+  { key: 'backup'   as SettingsTab, icon: 'database' as const },
+  { key: 'data'     as SettingsTab, icon: 'cube'     as const },
 ]
 const { copyToClipboard } = useClipboard()
 
@@ -2378,9 +2392,38 @@ onMounted(() => {
 }
 
 /* ============ Settings Tab Navigation ============ */
+
+/* Scroll container: thin scrollbar on PC, auto-hide on mobile */
+.settings-tabs-scroll {
+  scrollbar-width: thin;
+  scrollbar-color: transparent transparent;
+}
+.settings-tabs-scroll:hover {
+  scrollbar-color: rgb(0 0 0 / 0.15) transparent;
+}
+:root.dark .settings-tabs-scroll:hover {
+  scrollbar-color: rgb(255 255 255 / 0.2) transparent;
+}
+.settings-tabs-scroll::-webkit-scrollbar {
+  height: 3px;
+}
+.settings-tabs-scroll::-webkit-scrollbar-track {
+  background: transparent;
+}
+.settings-tabs-scroll::-webkit-scrollbar-thumb {
+  background: transparent;
+  border-radius: 3px;
+}
+.settings-tabs-scroll:hover::-webkit-scrollbar-thumb {
+  background: rgb(0 0 0 / 0.15);
+}
+:root.dark .settings-tabs-scroll:hover::-webkit-scrollbar-thumb {
+  background: rgb(255 255 255 / 0.2);
+}
+
 .settings-tabs {
-  @apply inline-flex min-w-full gap-1 rounded-2xl
-         border border-gray-100 bg-white/80 p-1.5 backdrop-blur-sm
+  @apply inline-flex min-w-full gap-0.5 rounded-2xl
+         border border-gray-100 bg-white/80 p-1 backdrop-blur-sm
          dark:border-dark-700/50 dark:bg-dark-800/80;
   box-shadow: 0 1px 3px rgb(0 0 0 / 0.04), 0 1px 2px rgb(0 0 0 / 0.02);
 }
@@ -2392,8 +2435,8 @@ onMounted(() => {
 }
 
 .settings-tab {
-  @apply relative flex flex-1 items-center justify-center gap-2
-         whitespace-nowrap rounded-xl px-4 py-2.5
+  @apply relative flex flex-1 items-center justify-center gap-1.5
+         whitespace-nowrap rounded-xl px-2.5 py-2
          text-sm font-medium
          text-gray-500 dark:text-dark-400
          transition-all duration-200 ease-out;
@@ -2420,7 +2463,7 @@ onMounted(() => {
 }
 
 .settings-tab-icon {
-  @apply flex h-7 w-7 items-center justify-center rounded-lg
+  @apply flex h-6 w-6 items-center justify-center rounded-lg
          transition-all duration-200;
 }