Expand description
memstead review-mark — read and move the per-mem review mark.
The mark is the engine’s one pointer per mem to the last
human-approved state (mem-repo state: every consumer of the mem
sees the same mark). list answers “what has un-reviewed
changes”; set moves a mem’s mark to an explicitly named state
(never implicitly “now” — writers may have advanced the mem
mid-review); clear returns a mem to the ordinary markless
state; diff reports the accumulated per-entity delta from the
mark to the current head, in the same change-envelope shape
memstead changes uses. Marks never gate writes — ignoring them
entirely is a first-class state.