Process Lifecycle Cleanup

Every child process needs an owner and a terminal cleanup path.

Contract

• Record the child process identity/handle at launch.
• Distinguish daemon-by-design from task-scoped children.
• On normal completion, error, timeout, cancellation, or parent exit, stop task-scoped children and wait for termination.
• Clean temporary ports, lock files, pipes, sockets, and working directories owned by the process.
• Never kill by broad process name when an exact PID/job/process tree is available.
• Verify shutdown: the process is gone and owned resources are released.

A UI closing while its worker remains alive is a failure. Cleanup errors must be surfaced when they can leave corrupt or conflicting state.