chatWithSystem and chatWithMessages each built the request, sent it, read
it and unwrapped the choice. Both now call postChat, which does that once.
The copies had already drifted: only chatWithMessages logged the raw
generation, so an unparseable nudge or query left nothing in the log to
read. Every path logs it now, tagged with the caller.
Verbatim move of chatMsg, chatReq, chatResp, phraseRepeatPenalty,
responseGrammar/ResponseGrammar, grammar() and logIfTruncated. The two
senders follow.
claude