The 8.0.6 checklist for this slice, which adds fields on party.updated
(an email and two default terms) and the invoicing settings it guards:
1. books_written_under_older_rules_still_open now hand-writes a party's
email and terms and an invoicing setting through JournalWriter, and the
books still open, verify and replay them.
2. A new old-books fixture, p4_s42_settings_parties, was written by the
version before this slice (1bfce915, through the old-books-writer
harness) with a party, a vendor, two posted entries and three settings,
and its expected.json from that version's code. This version opens it,
verifies it and reports its figures identically.
3. books_p2_served_cut_over_whole gains a refused invoicing setting before
the go-ahead; the same call succeeds after it.
4. documents_v2_is_its_own_feature: books that declared every earlier
feature stop at its declaration as newer, wait for the upgrade, and
name exactly it in the upgrade.
No figure moves (item 5): settings and party facts enter no report.
Merge does not need the owner's go-ahead; the live books refuse the new
party and setting writes with the upgrade remedy until he gives it.