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.
yinjianm