YearOrRange
Calendar year as a single `value`, a `min`/`max` range, or both. Years
are expressed as full integer years (CE / Common Era). The fields are independent
and all optional.
Display precedence: when both are present, prefer value (the headline year);
fall back to min/max for indicative display.
- maxType: null | integer | stringFormat: int32
Latest year in the range (e.g. 2005).
- minType: null | integer | stringFormat: int32
Earliest year in the range (e.g. 1990).
- valueType: null | integer | stringFormat: int32
Single calendar year (the headline year, or the midpoint of a range).