//! Final-answer recovery for trace mode (#1942).
//!
//! CLI providers stream every text block, the answer included, as
//! `IntermediateText` and return an empty `response.content`. Trace mode
//! folds each intermediate into the tool bubble as a clipped note and
//! posts nothing, so the empty-final guard would then skip the only
//! delivery the answer ever gets.
/// The text the final path should deliver: the final content when it has
/// any, otherwise (trace mode only) the last intermediate body that was
/// folded into the bubble instead of posted. With trace off an empty final
/// stays empty, because the intermediates were posted as real messages.
pub