V2_FIELDS list omitted prompt_signal and events — both are always produced
by parser and buildEpisodeFromContext, so the happy path is unaffected, but
a future ctx-fallback path that dropped them would silently write a
malformed episode. Add both to V2_FIELDS; appendEpisode now throws on either
being missing.
Tests: 2 new — appendEpisode throws when prompt_signal missing /
when events missing. 38/38 stop-hook tests green.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Дмитрий
7fc9b5935e