Deployment rehearsal on ultix-field 2026-09-02 caught it live: the
listener showed active but decode_stream never ran (stdbuf exec's
binaries only). Line-buffering moved inside decode_stream; the od
stage keeps its own stdbuf.
Rehearsal note: https://projects.knownelement.com/issues/355
Modern successor of the 2018 Perl doorman (snapshot in legacy/):
bash+coreutils HID decoder, HA webhook dispatch, systemd unit.
Offline decoder suite green (9 tests); shellcheck zero-warning.
Umbrella #345. Work item: https://projects.knownelement.com/issues/355