@onlyworlds/sdk 4.20.0

Added

• World calendars, Atlas's calendar code in the SDK so Lantern can name dates (Temper,
  h37 #4284): formatStep, formatYearLabel, breakdownStep, parseDate and the rest of
  Atlas's src/core/calendar.ts (Atlas 02d6a6d), plus worldCalendars,
  resolveCalendarLens and readCalendarValue from its calendar-lens.ts, on any element
  shape. CALENDAR_FIELD is atlas_calendar: Atlas owns the field, its meaning and its
  writes, and other tools read it (Skeld, h37 #4286).
• src/calendar/calendar.ts is Atlas's file byte for byte, recorded in
  src/calendar/SOURCES.json (Assembly's copy-drift); codegen/atlas-calendar.mjs re-copies it
  and ports Atlas's 48 kernel tests (TypeScript's transpiler, a five-matcher test/expect.mjs
  over node:test). Watched failing: a planted floorMod edit failed two tests and the record
  (EDITED); a lens edit failed its test. An app that imports none of it bundles none of it.