[Feature Request] Built-in timeZone data type #1100

Description

A built-in @type=timeZone data type that validates IANA time zone names (Europe/Madrid, UTC, America/Argentina/Buenos_Aires).

Motivation

A regex can only check the shape of the value, so the realistic mistake, a typo like Europe/Madird, passes validation and blows up later at runtime with a RangeError, far from the config that caused it. The runtime already knows the real list of zones, so the schema could check against it at load time.

Proposed Solution

Validate with Intl, which behaves the same under Node and Bun:

validate(val) {
 try {
  new Intl.DateTimeFormat("en", { timeZone: val });
 } catch {
  throw new ValidationError(`"${val}" is not a known IANA time zone`);
 }
}

# @type=timeZone
SALON_TIME_ZONE=Europe/Madrid

It's about 10 lines, which is why it feels like it belongs next to url, email, port and the other built-in types. Happy to send a PR if you'd take it.