feat(settings): 更新开关的界面与四语言文案

- 系统设置页加「定时检查更新」下拉（选项由 UPDATE_CHECK_INTERVALS 白名单
  生成，标签用 Record<UpdateCheckInterval, string> 保证漏项即编译错误）与
  「自动下载更新」开关
- 关于页：后台自动下载完成时用 statusDownloadedAuto 文案，与用户手动下载
  区分
- 四语言补齐 13 个键（含托盘气泡文案），已用 i18n parity 校验 617 键对齐

src/renderer/src/settings/AboutTab.tsx

@@ -84,7 +84,13 @@ export function AboutTab(): React.JSX.Element {
   }, [])
 
   const status = state?.status ?? 'idle'
-  const statusText = t(STATUS_TEXT[status]) + (state?.version ? ` v${state.version}` : '')
+  // A download the app started on its own reads differently from one the user
+  // pressed the button for — same state, different expectation about install.
+  const statusKey =
+    status === 'downloaded' && state?.auto
+      ? 'settings.about.statusDownloadedAuto'
+      : STATUS_TEXT[status]
+  const statusText = t(statusKey) + (state?.version ? ` v${state.version}` : '')
 
   return (
     <div className="about-tab">

src/renderer/src/settings/SettingsTabs.tsx

@@ -1,6 +1,7 @@
 import type { ReactNode } from 'react'
 import { useMemo, useState } from 'react'
 import { Input, InputNumber, Radio, Select, Switch } from 'antd'
+import { UPDATE_CHECK_INTERVALS, type UpdateCheckInterval } from '@shared/settings'
 import type { ThemeColors } from '@shared/theme'
 import { DEFAULT_LANGUAGE, LANGUAGES, t, type Language } from '@shared/i18n'
 import { isReservedAccelerator } from '@shared/reservedAccelerators'
@@ -345,6 +346,18 @@ export function RenderSettingsTab(): React.JSX.Element {
   )
 }
 
+/**
+ * Label for each offered interval. Keyed by the whitelist union rather than
+ * built ad hoc, so a new entry in UPDATE_CHECK_INTERVALS fails to type-check
+ * here until it has a label (and `0` keeps meaning "never").
+ */
+const UPDATE_INTERVAL_LABELS: Record<UpdateCheckInterval, string> = {
+  0: 'settings.system.updateCheckNever',
+  4: 'settings.system.updateCheck4h',
+  12: 'settings.system.updateCheck12h',
+  24: 'settings.system.updateCheck24h'
+}
+
 export function SystemSettingsTab(): React.JSX.Element {
   const settings = useSettingsStore((s) => s.settings)
   const updateSystem = useSettingsStore((s) => s.updateSystem)
@@ -403,6 +416,31 @@ export function SystemSettingsTab(): React.JSX.Element {
           />
         }
       />
+      <SettingRow
+        label={t('settings.system.updateCheckInterval')}
+        desc={t('settings.system.updateCheckIntervalDesc')}
+        control={
+          <Select
+            className="settings-select"
+            value={settings.system.updateCheckIntervalHours ?? 4}
+            onChange={(value) => void updateSystem({ updateCheckIntervalHours: value })}
+            options={UPDATE_CHECK_INTERVALS.map((hours) => ({
+              value: hours,
+              label: t(UPDATE_INTERVAL_LABELS[hours])
+            }))}
+          />
+        }
+      />
+      <SettingRow
+        label={t('settings.system.autoDownload')}
+        desc={t('settings.system.autoDownloadDesc')}
+        control={
+          <Switch
+            checked={settings.system.autoDownloadUpdate === true}
+            onChange={(checked) => void updateSystem({ autoDownloadUpdate: checked })}
+          />
+        }
+      />
       <SettingRow
         label={t('settings.system.closeAction')}
         desc={t('settings.system.closeActionDesc')}

src/shared/i18n/dicts/en/main.ts

@@ -17,6 +17,10 @@ const main: Record<string, string> = {
 
   'main.updater.feedFailed': 'Gitea feed: {gitea}; GitHub: {github}',
   'main.updater.checkTimeout': 'Update check timed out',
+  'main.updater.notifyAvailableTitle': 'Update available',
+  'main.updater.notifyAvailableContent': 'OpenTerminal v{version} is available',
+  'main.updater.notifyDownloadedTitle': 'Update downloaded',
+  'main.updater.notifyDownloadedContent': 'v{version} downloaded — it installs when you quit the app',
 
   'main.ssh.connectTimeout': 'Connection timed out ({host}:{port})',
   'main.ssh.saveFingerprintFailed': 'Failed to save the host fingerprint: {detail}',

src/shared/i18n/dicts/en/settings.ts

@@ -94,6 +94,16 @@ const settings: Record<string, string> = {
   'settings.system.preventSleep': 'Prevent system sleep',
   'settings.system.preventSleepDesc':
     'While on, OpenTerminal keeps the system from sleeping automatically; when off, the system follows its own power settings',
+  'settings.system.updateCheckInterval': 'Periodic update check',
+  'settings.system.updateCheckIntervalDesc':
+    'Check for new versions periodically in the background (startup and manual checks always work)',
+  'settings.system.updateCheckNever': 'Never',
+  'settings.system.updateCheck4h': 'Every 4 hours',
+  'settings.system.updateCheck12h': 'Every 12 hours',
+  'settings.system.updateCheck24h': 'Every 24 hours',
+  'settings.system.autoDownload': 'Download updates automatically',
+  'settings.system.autoDownloadDesc':
+    'Silently download new versions in the background; installing stays your call (it installs when you quit the app)',
   'settings.system.restoreSession': 'Restore last session on startup',
   'settings.system.restoreSessionDesc':
     'Restore the split layout on the next launch and return each terminal to its last directory; when off, OpenTerminal always starts with a single terminal',
@@ -308,6 +318,7 @@ const settings: Record<string, string> = {
   'settings.about.statusLatest': 'Already up to date',
   'settings.about.statusDownloading': 'Downloading…',
   'settings.about.statusDownloaded': 'Download complete — restart to install',
+  'settings.about.statusDownloadedAuto': 'Downloaded in the background — installs when you quit',
   'settings.about.statusError': 'Check failed',
   'settings.about.statusDev': 'Update checks are unavailable in development mode',
   'settings.about.autoCheck': 'Check automatically at startup',

src/shared/i18n/dicts/ja/main.ts

@@ -17,6 +17,10 @@ const main: Record<string, string> = {
 
   'main.updater.feedFailed': 'Gitea フィード: {gitea}；GitHub: {github}',
   'main.updater.checkTimeout': '更新の確認がタイムアウトしました',
+  'main.updater.notifyAvailableTitle': '新しいバージョンがあります',
+  'main.updater.notifyAvailableContent': 'OpenTerminal v{version} が利用可能です',
+  'main.updater.notifyDownloadedTitle': 'アップデートをダウンロードしました',
+  'main.updater.notifyDownloadedContent': 'v{version} をダウンロードしました — 終了時にインストールされます',
 
   'main.ssh.connectTimeout': '接続がタイムアウトしました ({host}:{port})',
   'main.ssh.saveFingerprintFailed': 'ホスト鍵のフィンガープリントを保存できませんでした: {detail}',

src/shared/i18n/dicts/ja/settings.ts

@@ -91,6 +91,16 @@ const settings: Record<string, string> = {
   'settings.system.preventSleep': 'スリープを防止',
   'settings.system.preventSleepDesc':
     'オンにすると OpenTerminal がシステムの自動スリープを防ぎます。オフにすると OS の設定どおりにスリープします',
+  'settings.system.updateCheckInterval': '定期アップデート確認',
+  'settings.system.updateCheckIntervalDesc':
+    'バックグラウンドで定期的に新バージョンを確認します（起動時と手動確認は常に有効）',
+  'settings.system.updateCheckNever': 'なし',
+  'settings.system.updateCheck4h': '4 時間ごと',
+  'settings.system.updateCheck12h': '12 時間ごと',
+  'settings.system.updateCheck24h': '24 時間ごと',
+  'settings.system.autoDownload': 'アップデートを自動ダウンロード',
+  'settings.system.autoDownloadDesc':
+    '新バージョンをバックグラウンドで自動ダウンロードします（インストールは終了時に実行されます）',
   'settings.system.restoreSession': '起動時に前回のセッションを復元',
   'settings.system.restoreSessionDesc':
     '次回の起動で分割レイアウトを復元し、各ターミナルを前回のディレクトリに戻します。オフにすると毎回 1 つのターミナルで起動します',
@@ -303,6 +313,7 @@ const settings: Record<string, string> = {
   'settings.about.statusLatest': '最新バージョンです',
   'settings.about.statusDownloading': 'ダウンロードしています…',
   'settings.about.statusDownloaded': 'ダウンロード完了。再起動してインストールできます',
+  'settings.about.statusDownloadedAuto': 'バックグラウンドでダウンロード完了 — 終了時にインストールされます',
   'settings.about.statusError': '確認に失敗しました',
   'settings.about.statusDev': '開発モードでは更新を確認できません',
   'settings.about.autoCheck': '起動時に自動で確認',

src/shared/i18n/dicts/zh-CN/main.ts

@@ -17,6 +17,10 @@ const main: Record<string, string> = {
 
   'main.updater.feedFailed': '国内源: {gitea}；GitHub: {github}',
   'main.updater.checkTimeout': '检查更新超时',
+  'main.updater.notifyAvailableTitle': '发现新版本',
+  'main.updater.notifyAvailableContent': 'OpenTerminal v{version} 已可用',
+  'main.updater.notifyDownloadedTitle': '更新已下载',
+  'main.updater.notifyDownloadedContent': 'v{version} 已下载完成，退出应用时将自动安装',
 
   'main.ssh.connectTimeout': '连接超时 ({host}:{port})',
   'main.ssh.saveFingerprintFailed': '保存主机指纹失败: {detail}',

src/shared/i18n/dicts/zh-CN/settings.ts

@@ -89,6 +89,16 @@ const settings: Record<string, string> = {
   'settings.system.preventSleep': '阻止系统休眠',
   'settings.system.preventSleepDesc':
     '开启后 OpenTerminal 将阻止系统自动休眠；关闭则允许系统按系统设置休眠',
+  'settings.system.updateCheckInterval': '定时检查更新',
+  'settings.system.updateCheckIntervalDesc':
+    '后台按周期自动检查新版本（启动时与手动检查始终可用）',
+  'settings.system.updateCheckNever': '从不',
+  'settings.system.updateCheck4h': '每 4 小时',
+  'settings.system.updateCheck12h': '每 12 小时',
+  'settings.system.updateCheck24h': '每 24 小时',
+  'settings.system.autoDownload': '自动下载更新',
+  'settings.system.autoDownloadDesc':
+    '发现新版本时在后台静默下载；安装时机仍由你决定（退出应用时会自动安装）',
   'settings.system.restoreSession': '启动时恢复上次会话',
   'settings.system.restoreSessionDesc':
     '下次启动恢复分屏布局，并让每个终端回到它上次所在的目录；关闭则每次都以单个终端启动',
@@ -292,6 +302,7 @@ const settings: Record<string, string> = {
   'settings.about.statusLatest': '已经是最新版本',
   'settings.about.statusDownloading': '正在下载…',
   'settings.about.statusDownloaded': '下载完成，可重启安装',
+  'settings.about.statusDownloadedAuto': '已在后台下载完成，退出时自动安装',
   'settings.about.statusError': '检查失败',
   'settings.about.statusDev': '开发模式不支持更新检查',
   'settings.about.autoCheck': '启动时自动检查',

src/shared/i18n/dicts/zh-TW/main.ts

@@ -17,6 +17,10 @@ const main: Record<string, string> = {
 
   'main.updater.feedFailed': '國內來源: {gitea}；GitHub: {github}',
   'main.updater.checkTimeout': '檢查更新逾時',
+  'main.updater.notifyAvailableTitle': '發現新版本',
+  'main.updater.notifyAvailableContent': 'OpenTerminal v{version} 已可用',
+  'main.updater.notifyDownloadedTitle': '更新已下載',
+  'main.updater.notifyDownloadedContent': 'v{version} 已下載完成，結束應用程式時將自動安裝',
 
   'main.ssh.connectTimeout': '連線逾時 ({host}:{port})',
   'main.ssh.saveFingerprintFailed': '儲存主機指紋失敗: {detail}',

src/shared/i18n/dicts/zh-TW/settings.ts

@@ -89,6 +89,16 @@ const settings: Record<string, string> = {
   'settings.system.preventSleep': '防止系統休眠',
   'settings.system.preventSleepDesc':
     '開啟後 OpenTerminal 會防止系統自動休眠；關閉則允許系統依本身的設定休眠',
+  'settings.system.updateCheckInterval': '定時檢查更新',
+  'settings.system.updateCheckIntervalDesc':
+    '背景依週期自動檢查新版本（啟動時與手動檢查始終可用）',
+  'settings.system.updateCheckNever': '永不',
+  'settings.system.updateCheck4h': '每 4 小時',
+  'settings.system.updateCheck12h': '每 12 小時',
+  'settings.system.updateCheck24h': '每 24 小時',
+  'settings.system.autoDownload': '自動下載更新',
+  'settings.system.autoDownloadDesc':
+    '發現新版本時在背景靜默下載；安裝時機仍由你決定（結束應用程式時會自動安裝）',
   'settings.system.restoreSession': '啟動時還原上次工作階段',
   'settings.system.restoreSessionDesc':
     '下次啟動時還原分割版面，並讓每個終端回到上次所在的目錄；關閉則每次都以單一終端啟動',
@@ -292,6 +302,7 @@ const settings: Record<string, string> = {
   'settings.about.statusLatest': '目前已是最新版本',
   'settings.about.statusDownloading': '正在下載…',
   'settings.about.statusDownloaded': '下載完成，可重新啟動安裝',
+  'settings.about.statusDownloadedAuto': '已在背景下載完成，結束時自動安裝',
   'settings.about.statusError': '檢查失敗',
   'settings.about.statusDev': '開發模式不支援檢查更新',
   'settings.about.autoCheck': '啟動時自動檢查',