Account for every unit of a fee on a settled transfer

Everyone quotes a fee; nobody says where it WENT. This reconstructs a completed transfer unit by unit — what was sent, what arrived, and every component of the difference, each labelled with who it was paid to and how the figure was derived (destination payout gas, Robyn margin, or a Robyn SUBSIDY when we absorbed a loss, which is reported as such). Anything that cannot be attributed is returned as unattributed rather than folded into another line to make the arithmetic look tidy — a breakdown that always sums perfectly is one that is hiding something.