A representative list for runtimes without Intl.supportedValuesOf
(Node < 18, older WebViews): the zones a clinic or a patient is likely to
be in, one or two per region, every UTC offset covered. Never the source
of truth — listTimeZoneIds prefers the runtime's own table — and
never the validator: isKnownTimeZone asks Intl, so an id outside
this list that the runtime knows is still accepted.
A representative list for runtimes without
Intl.supportedValuesOf(Node < 18, older WebViews): the zones a clinic or a patient is likely to be in, one or two per region, every UTC offset covered. Never the source of truth — listTimeZoneIds prefers the runtime's own table — and never the validator: isKnownTimeZone asksIntl, so an id outside this list that the runtime knows is still accepted.