Upgrade run-system with an optional visible terminal mode and persistent process tracking.

The manager should retain the launched process PID/process-group identity and expose safe lifecycle operations:

• run-system
• kill-system

The implementation must target only the exact Staxis process tree started by the manager. It must never terminate processes by generic names such as node or node.exe.

Add a configuration flag to choose between visible terminal output and hidden detached execution. Persist enough runtime metadata to detect and clean stale PID records safely.

This upgrade will make emergency termination and manager-controlled restart possible without turning the manager into a mandatory permanent supervisor.