Claude Code TaskStop kills the job's process tree AND its process group

Tested on Linux, bash 5.2.21. When a normal Bash tool call returns, background children survive: ( sleep N ) &, nohup sh -c ... & and a plain sleep N & were all alive in the next call, reparented to pid 1 and still in the old tool shell's pgid. Stopping a run_in_background task with TaskStop killed every child of the job, including setsid sleep and nohup setsid sleep (own pgid and sid but still children), and also a double-forked sleep that was reparented to pid 1 but still in the job's pgid. The only survivor was setsid sh -c 'cmd >/dev/null 2>&1 &': new group, then reparented to pid 1 when the sh exited. nohup alone protects nothing here. Record pids in files, and check with kill -0 rather than pgrep -f, which can match the tool shell's own argv.