The dumper was printing ``stream=None target=None`` for every
message because it read those fields off the message dicts, but
the recipe renderer keeps them in parallel arrays
(``message_streams`` / ``target_message_indices`` in
COMPLEMENTARY_DATA) so the chat template doesn't see unknown
keys. Zip them back into the dump-time dicts so the printed
metadata is accurate.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
c3503b774f