Normative: Intl Locale API proposal for Stage 4

[FrankYFTang]

The spec text change for https://github.com/tc39/proposal-intl-locale-info

We should discuss this once Intl Locale Info API is ready to move to stage 4.
This is one of the require task.

[sffc]

TG2 discussion: https://github.com/tc39/ecma402/blob/main/meetings/notes-2024-12-19.md#intl-locale-info-api-for-stage-4

[sffc]

TG2 approval: https://github.com/tc39/ecma402/blob/main/meetings/notes-2025-10-13.md#intl-locale-info-for-stage-4-1

[FrankYFTang]

Ready to be review for merging if Intl Locale Info advanced to Stage 4. Still need to merge tc39/proposal-intl-locale-info#92 into this PR first if TC39 approve both

[FrankYFTang]

@ben-allen @gibson042 @ryzokuken will be nice if you can voice your concern or support about this PR from the editor's view ASAP before the TG1. Thanks

[gibson042]

A few things to fix before approval.

[gibson042]

This logic seems like it belongs in TimeZonesOfLocale, replacing the assertion and bringing it in better alignment with LocaleDirection.

         1. Let _region_ be GetLocaleRegion(_loc_.[[Locale]]).
-        1. Assert: _region_ is not *undefined*.
+        1. If _region_ is *undefined*, return *undefined*.
         1. Let _list_ be a List of unique canonical time zone identifiers, which must be String values indicating a canonical Zone name of the IANA Time Zone Database, of those in common use in _region_. The list is empty if no time zones are commonly used in _region_. The list is sorted according to lexicographic code unit order.
         1. Return CreateArrayFromList( _list_ ).

Suggested change

	1. Let _region_ be GetLocaleRegion(_loc_.[[Locale]]).
	1. If _region_ is *undefined*, return *undefined*.

[FrankYFTang]

PTAL
I adress your feedback
I also merge the last PR in the proposal

and in 2025-11-18 TC39 this stage 4 proposal is advanced to stage 4

[FrankYFTang]

PTAL

[sffc]

TG1 approval for Stage 4: https://github.com/tc39/notes/blob/main/meetings/2025-11/november-18.md#intl-locale-info-api-for-stage-4 (should merge PR 92)

[gibson042]

There are a few editorial nits that I'd be happy to address myself, but this PR cannot merge until we resolve the getTextInfo output question.

[FrankYFTang]

PTAL