carlos / platform Public

Fixes #175's production finding: a busy instance never reached ready because runMoveRound promoted only on a zero-change round. Now a round that copied at most CARLOSMOVEREADYDELTABYTES (default 16 MiB) promotes; the cut's quiesce, final checkpoint and byte-exact final mirror keep correctness. MirrorPrefix now reports bytes copied. Cut, abort and landing paths unchanged. Astra code review in progress.