Adds two DeadlineRule types used to clear the sequence-diagram Frist [REVIEW] badges:
terminiert— a spätester-ÜT/ÜZ deadline fixed relative to an external anchor
(Zahlungsziel, Änderungstermin, …) or recurring daily, rendered as a compact inline tag.reference— a real but irreducible Frist (table/SD/contract ref, conditional, range),
rendered as an(i)note without[REVIEW].
New optional fields direction / anchor / recurring; existing rules deserialize unchanged.
Consumed by makorele (parser) and the mako_prozesse webapp.