@onlyworlds/sdk 4.42.2

Two calendar reading fixes, found writing the atlas_calendar profile's conformance fixture (OW Council h58 #8943, #8946).

Fixed

• A down era has no year zero, even when its pivot falls mid-year. Its year is now counted from the year holding the step just before the pivot, which reads year_base (1 by default). With the pivot mid-year, the earlier steps of the pivot's own year read year 0 ("0 BG") and every year before it one lower; with the pivot on a year's first step, nothing changes. The mirror of an up era, whose first partial year is year 1.
• Equal-start eras resolve by a stated rule: an up era over a down one, then the later era in the list. The comparator returned -1 for any pair led by an up era, so two eras of one direction came out in the sort's order rather than the list's.