Represents a collection of time periods (cycles).
Represents a Zeit (time) object in the database timezone (UTC).
A Zod schema for validating time zone strings. It ensures that only valid time zones from the Timezone object are accepted.
Represents a Zeit (time) object in the user's timezone.
Represents a Zeit (time) object with timezone awareness. This class serves as a factory for creating UserZeit and DatabaseZeit instances.