Set Age Threshold

The age below which this school's students need a parent's signed consent. Admins only, same shape as /required. Body: {"age": 16}.

Changing the number does NOT re-judge anyone already marked. A student marked a minor stays a minor, and an adult stays an adult, until a coordinator corrects that student on the roster, as today. Only the question a student is asked from now on, and what the screens say, follow the new number.