Tool contract 3.15.1

Three things the Phase 2 acceptance read surfaced.

• finish_time on war_current.standings[], the exact week's war_history.standings[] and race_finished_at is null for a clan that did not finish: the API marks those with epoch zero (1969-12-31T23:59:59Z) and the sentinel was served as a time.
• Each day's standings on war_history.days[] and war_current.days_closed[] carry rank (1-based, null while unranked) beside end_of_day_rank (the API's 0-based value, -1 unranked).
• The recorder now keeps a section's fourth war day, which is first reported in the next section's polls and was dropped: days[] carries four entries on a full week once the archive re-walk has run.

Additive; the added field is rank.