Passwords failed on 10/16 challenges while state.json looked correct:
- only the 6 native GEMASTIK XVIII images provision 'ctfuser'; every imported
XVI/XVII image does 'echo root:${PASSWORD} | chpasswd' and logs in as root.
set_ssh_passwords() hardcoded ctfuser, so chpasswd set a password on an
account nobody uses -> 'Permission denied' everywhere.
Registry gains a per-challenge 'ssh_user'; chpasswd now targets the real
login (and ctfuser/ctf when present) and reports failures loudly.
- phew checker: chall.py block-buffers stdout through the docker exec pipe
(PYTHONUNBUFFERED now set) and leaks chall.py inside the container on
timeout (26 orphans, container saturated) -> reaps the whole exec process
group. Startup does a fresh Pailier keygen (~12 s) so crypto reads need
_CRYPTO_TIMEOUT, not the 5 s prompt default.
Adds panel/verify_ssh_creds.py (proves the state->container binding from
inside via a real login), audit_ssh_users.sh, reset_runtime.sh.
