One exchange from a session's conversation log (see history). user is the
end-user's message, assistant the companion's reply; either may be '' for
a paused / assistant-only row. ts is epoch ms.
Files the assistant reply produced (CR-729) — the same structural list
its companion.message carried, so a restored transcript keeps the
download affordance. Absent on a text-only turn and on older servers.
One exchange from a session's conversation log (see
history).useris the end-user's message,assistantthe companion's reply; either may be''for a paused / assistant-only row.tsis epoch ms.