feat(hid): 添加 Linux 键盘与 SysRq 快捷键 (#307)

控制台增加独立快捷键菜单，提供常用组合键和 Linux SysRq 指令，虚拟键盘补充 Linux 布局。
通过可靠且有序的 WebSocket 发送组合键，取消或失败时逐一释放按键，防止修饰键残留。
执行期间避免物理键盘与虚拟键盘交错输入，断连、失焦和切换布局时停止执行。
修正焦点移动后的物理按键释放，并将原虚拟键盘组合键迁移到统一菜单。

验证：独立暂存快照前端构建通过；6 项快捷键单测及 5 组浏览器测试通过，覆盖组合键序列、失败清理、取消及键盘焦点。

Refs #307

web/src/i18n/en-US.ts

@@ -109,6 +109,36 @@ export default {
     selectResolution: 'Select resolution...',
     selectFps: 'Select FPS...',
   },
+  shortcuts: {
+    close: "Close shortcuts",
+    unavailable: "HID is disconnected",
+    releaseKeys: "Release held keys first",
+    stopped: "Shortcut stopped",
+    failed: "Shortcut interrupted. Check the HID connection.",
+    sysrqHelp: "SysRq is PrintScreen. SysRq must be enabled on the target Linux system. Open kernel documentation",
+    actions: {
+      'ctrl-alt-delete': "Ctrl+Alt+Del",
+      'task-manager': "Task Manager",
+      'switch-window': "Switch windows",
+      'close-window': "Close window",
+      'lock-windows': "Lock Windows",
+      'run': "Run",
+      'tty1': "Switch to virtual terminal 1",
+      'tty2': "Switch to virtual terminal 2",
+      'restart-x': "Restart the X server",
+      'force-quit': "Force Quit Applications",
+      'sysrq-h': "Show help",
+      'sysrq-f': "Invoke the OOM killer",
+      'sysrq-m': "Show memory information",
+      'sysrq-t': "Show tasks",
+      'sysrq-r': "Restore keyboard mode",
+      'sysrq-e': "Terminate all processes except init",
+      'sysrq-i': "Kill all processes except init",
+      'sysrq-s': "Sync disks",
+      'sysrq-u': "Remount filesystems read-only",
+      'sysrq-b': "Reboot immediately without syncing disks",
+    },
+  },
   common: {
     loading: 'Loading...',
     save: 'Save',
@@ -236,6 +266,7 @@ export default {
     power: 'Power',
     keyboard: 'Virtual Keyboard',
     keyboardTip: 'Show virtual keyboard',
+    shortcuts: 'Shortcuts',
     webTerminal: 'Web Terminal',
     stats: 'Stats',
     statsTip: 'View connection statistics',