feat(system): 添加设备信息及重启关机控制

关于页展示宿主系统、处理器、架构、内核和资源占用，合并同一文件系统上的系统与 MSD 容量。
新增 Linux 宿主机重启和关机接口，在其他设置中提供二次确认、请求互斥及失败提示。
修正 Linux 磁盘已用空间计算，并补充设备信息和电源控制的后端单元测试。

验证：独立暂存快照前端构建通过；6 项后端测试通过；设置页保存、系统信息及模拟电源控制浏览器测试通过。

web/src/i18n/settings-ui.ts

@@ -1,12 +1,49 @@
 export const settingsUiZh = {
   watchdogAutoReset: '启用自动复位',
+  deviceControls: '设备操作',
+  deviceControlsHelp: '管理运行 One-KVM 的设备',
+  reboot: '重启',
+  poweroff: '关机',
+  rebootConfirm: '确认重启设备？',
+  poweroffConfirm: '确认关闭设备？',
+  rebootDescription: '将重启运行 One-KVM 的设备，当前连接会中断。启动完成后可重新连接。',
+  poweroffDescription: '将关闭运行 One-KVM 的设备，当前连接会中断。关机后需要手动重新上电。',
+  rebootSent: '重启请求已发送，请等待设备重新启动后再连接。',
+  poweroffSent: '关机请求已发送，设备即将关闭。',
+  deviceActionFailed: '操作请求未能发送，请重试。',
+
   mcpRate: '请求频率（次/秒）',
   help: '查看提示',
   back: '返回控制台',
   saveCapture: '保存采集设置',
   saveEncoder: '保存编码设置',
   saveConnection: '保存连接设置',
+  load: '系统监控',
+  loadHelp:
+    '显示 CPU、内存和分区的实际占用比例。系统与 MSD 位于同一文件系统时合并显示，不重复统计容量。',
+  cpu: 'CPU 占用',
+  memory: '内存占用',
+  systemDisk: '系统分区占用',
+  msdDisk: 'MSD 分区占用',
+  sharedDisk: '系统 / MSD 分区占用',
+  cores: '{count} 核处理器',
+  systemInfo: '版本与系统',
+  systemInfoHelp:
+    '报告问题时，可提供软件版本、系统、处理器、架构、内核与主机名，方便定位设备环境。',
+  softwareVersion: '软件版本',
+  operatingSystem: '操作系统',
+  processor: '处理器',
+  architecture: '系统架构',
+  kernel: '内核版本',
+  hostname: '主机名',
+  copyInfo: '复制信息',
+  copied: '信息已复制',
+  copyFailed: '复制失败，请手动选择信息',
+  unavailable: '暂不可用',
   project: '项目主页',
+  docs: '使用文档',
+  feedback: '反馈问题',
+  loadFailed: '无法刷新系统信息，暂时保留最近一次读取的数据。',
   featuresHelp:
     'USB 功能会按当前驱动与设备能力提供。修改后只保存本卡片配置，设备可能重新识别 USB 连接。',
   identifiers: '高级设备标识',
@@ -22,13 +59,52 @@ export const settingsUiZh = {
 }
 export const settingsUiEn = {
   watchdogAutoReset: 'Enable automatic recovery',
+  deviceControls: 'Device controls',
+  deviceControlsHelp: 'Manage the device running One-KVM',
+  reboot: 'Restart',
+  poweroff: 'Shut down',
+  rebootConfirm: 'Restart this device?',
+  poweroffConfirm: 'Shut down this device?',
+  rebootDescription:
+    'The device running One-KVM will restart and disconnect this session. Reconnect after startup.',
+  poweroffDescription:
+    'The device running One-KVM will shut down and disconnect this session. You will need to power it on manually.',
+  rebootSent: 'Restart requested. Reconnect after the device starts up.',
+  poweroffSent: 'Shutdown requested. The device will turn off shortly.',
+  deviceActionFailed: 'Could not send the request. Please try again.',
+
   mcpRate: 'Requests per second',
   help: 'Show help',
   back: 'Back to console',
   saveCapture: 'Save capture',
   saveEncoder: 'Save encoder',
   saveConnection: 'Save connection',
+  load: 'System monitoring',
+  loadHelp:
+    'Actual CPU, memory and filesystem usage. System and MSD storage share one indicator when they belong to the same filesystem.',
+  cpu: 'CPU usage',
+  memory: 'Memory usage',
+  systemDisk: 'System partition',
+  msdDisk: 'MSD partition',
+  sharedDisk: 'System / MSD partition',
+  cores: '{count} CPU cores',
+  systemInfo: 'Version & system',
+  systemInfoHelp:
+    'Include the software version, operating system, processor, architecture, kernel and hostname when reporting an issue.',
+  softwareVersion: 'Software version',
+  operatingSystem: 'Operating system',
+  processor: 'Processor',
+  architecture: 'Architecture',
+  kernel: 'Kernel version',
+  hostname: 'Hostname',
+  copyInfo: 'Copy information',
+  copied: 'Information copied',
+  copyFailed: 'Copy failed. Select and copy the information manually.',
+  unavailable: 'Unavailable',
   project: 'Project',
+  docs: 'Documentation',
+  feedback: 'Report an issue',
+  loadFailed: 'Could not refresh system information. Showing the most recent data.',
   featuresHelp:
     'Available USB functions depend on the driver and hardware. Saving applies only this card and may reconnect the USB device.',
   identifiers: 'Advanced device identity',