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/en-US.json

@@ -626,6 +626,7 @@
     "errorPrefix": "Error:",
     "loading": "Waiting for data...",
     "cpuModelLabel": "CPU Model:",
+    "cpuCoresValue": "{count} cores",
     "osLabel": "OS:",
     "cpuLabel": "CPU:",
     "memoryLabel": "Memory:",
@@ -1627,6 +1628,7 @@
     "selectServerTitle": "Select server to connect",
     "showTransferProgressTooltip": "Show/Hide Transfer Progress",
     "newTerminalTooltip": "Open another terminal for the current server",
+    "closeConnectionGroupTooltip": "Close all terminals for {name} ({count})",
     "openConnectionPickerTooltip": "Choose another server",
     "terminalBadge": "Terminal {index}",
     "serverEntryTitle": "{name} · {count} terminals",

packages/frontend/src/locales/ja-JP.json

@@ -1365,6 +1365,7 @@
         "bytesPerSecond": "B/秒",
         "cpuLabel": "CPU:",
         "cpuModelLabel": "CPU モデル:",
+        "cpuCoresValue": "{count} コア",
         "diskLabel": "ディスク:",
         "errorPrefix": "エラー:",
         "gigaBytes": "GB",
@@ -1587,6 +1588,7 @@
           "selectServerTitle": "接続するサーバーを選択",
           "showTransferProgressTooltip": "転送進捗の表示/非表示",
           "newTerminalTooltip": "現在のサーバーに新しいターミナルを追加",
+          "closeConnectionGroupTooltip": "{name} の端末をすべて閉じる ({count} 件)",
           "openConnectionPickerTooltip": "別のサーバーを選択",
           "terminalBadge": "端末 {index}"
       },

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",