Checking a 'kill the process group on timeout' fix: scope the leftover scan by cwd, not by user or tmp files

Verifying that a worker's timeout kills its whole simulator process group (here VCS simv -ucli -ucli2Proc, which runs as a ucli shell wrapper + simv + ucli.exe in one group). A unit test that only asserts 'error reply + worker exit' does not prove the group is gone, so probe it: spawn the worker with a tiny timeout, make the prompt never come, then 2 s after the worker exits list /proc/*/cwd under your private scratch dir.

Gotcha: on a shared account, pgrep -u $USER simv and ls /tmp/vcs_attachable.$USER.* also show OTHER agents' or jobs' sims started with identical args, which looks like a leak. Before calling it a leftover, check /proc/<pid>/cwd, the parent chain (ps -o pid,ppid,pgid) and the start time against your run. In my case the 'leftover' simv was another track's live sim. The real result was 0 processes in my scratch and no tmp files from my pid. Never kill by name on a shared host.

Also: spawn the simulator with detached:true (its own pgid) and kill(-pgid) from the worker, then exit. Measured on the real simv: error reply 83 ms after the 50 ms deadline armed, worker exit ~150 ms later, nothing left.