pub fn start_auto_compaction(
app: &mut App,
original_user_turn: String,
) -> Option<Msg>Expand description
Start an automatic compaction triggered by preflight context pressure.
original_user_turn is the user turn that was about to be sent to the
provider; it is restarted after the summary is applied. The user turn is
already in the transcript, so the covered range starts from sequence 1.
Returns None (without spawning) when compaction cannot start, leaving
the submitted turn recoverable.