Collector and mutator watcher subprocesses were spawned without
start_new_session=True, leaving them in the parent's process group.
SIGHUP (sent when the controlling terminal closes) killed both
processes silently — stdout/stderr were DEVNULL so the crash was
invisible.
Also update test_services and test_composer to reflect the ssh plugin
no longer using Cowrie env vars (replaced with SSH_ROOT_PASSWORD /
SSH_HOSTNAME matching the real_ssh plugin).
anti
a6063efbb9