An inherited HERMES_TUI=1 or a `display.interface: tui` config default sent
kanban workers into the Ink TUI, whose no-TTY bail-out exits 0 without doing
the task — every attempt ended in "protocol violation". Two layers:
- _default_spawn pins `--cli` (highest-precedence interface flag) and strips
HERMES_TUI from the child env (covers older builds on PATH).
- _resolve_use_tui gates ambient TUI prefs (env/config) behind a real TTY;
an explicit --tui still wins so the informative bail-out stays reachable.
Brooklyn Nicholson
Teknium