Vocabulary guard mirror hole: a piezasDentarias row deleted out from under a scope member

fn_lookupOptionsForbidOrphaningScopeMembers fires on lookupOptions deactivation and has no equivalent for the relation-backed half: deleting a piezasDentarias row leaves any vocabularyScopeMembers row naming its codigoFdi pointing at nothing, with no error and no log line. Symmetric to the hole ENAMEL-42 closes on the insert side, opposite direction. The schema cannot carry a real FK here because the member table is polymorphic across vocabulary sources, which is why both halves are triggers. Raised by db-terra-cc at the end of the ENAMEL-42 deliverable (db-terra-cc-mtx7m0jylkhq) and explicitly left out of scope there.