feat(workspace): add cpu core status display and safer quick command actions

Expose `cpuCores` in backend status collection with multi-command fallback
and surface it in the status panel as a localized CPU core badge under the
CPU model.

Adjust terminal group UX by adding a server-level close-all control in the
SSH tab group header.

Reduce accidental quick command execution by switching list interaction to
single-click select + double-click execute, while preserving keyboard Enter
and context-menu execution paths.

packages/frontend/src/locales/zh-CN.json

@@ -626,6 +626,7 @@
     "errorPrefix": "错误:",
     "loading": "等待数据...",
     "cpuModelLabel": "CPU 型号:",
+    "cpuCoresValue": "{count} 核",
     "osLabel": "系统:",
     "cpuLabel": "CPU:",
     "memoryLabel": "内存:",
@@ -1631,6 +1632,7 @@
     "selectServerTitle": "选择要连接的服务器",
     "showTransferProgressTooltip": "显示/隐藏传输进度",
     "newTerminalTooltip": "为当前服务器新增终端",
+    "closeConnectionGroupTooltip": "关闭 {name} 的全部终端（{count} 个）",
     "openConnectionPickerTooltip": "选择其他服务器",
     "terminalBadge": "终端 {index}",
     "serverEntryTitle": "{name} · {count} 个终端",