prepare, execute, advance, evaluate, commit, then the boundary's ratchet capture and rollback,
in the order the stream runs them. The frame owns the remainder, the frame counter, the frame on
screen, the mask and the blocked-direction window; the sim loop keeps the feed, the event log,
the milestone archive between commit and boundary, and the checkpoints. Two moves between
disjoint state change no byte: the visual frame is installed at commit, and the stimulations
follow the scene's observation. The FLY_TRACE of a run from the rung-10 checkpoint is
byte-identical to the one the inline hooks wrote.