Store checkpoint turns as validated blobs and restore prefetched parent turns so forked conversations retain their replay history and rewind prefix.
Co-authored-by: Cursor <cursoragent@cursor.com>
Cursor may reuse the same request_id for a later turn and restart
append_seqno from 1. Accept seq=1 after progress as a sequence restart
when idle so tool results are not discarded as stale forever.