Gibbs refresh of the latent normal matrix Z for the
censored-binary (cbin) family, where each actor emits a capped
set of binary nominations. Within every sending row the update honours
three order constraints: a nominated tie has a positive latent value,
every nominated tie dominates every non-nominated tie, and a
non-nominated tie in a row that has not spent its full nomination
budget (odobs < odmax) is held below zero. Reciprocal cells are
coupled through the dyadic correlation rho; the self-loop
diagonal and any missing cells are redrawn from their unconstrained
conditionals.