Motivating transcript: piped `error xxxx` then interactive `set errorInfo`
shows tcllib virtchannel boot noise (caught `unset timer`) instead - the
restart boundary discards run-1's code interp, and bare ::errorInfo is
clobbered by internal caught errors anyway. Detail file records the two
mechanisms and design points (capture at the repl error-reporting site,
tsv/exitinfo handover, punk-owned record + one-line first-prompt notice,
quiet on clean pipes).
Assisted-by: harness=claude; primary-model=claude-fable-5; api-location=anthropic.com
Julian Noble