support az-AZ language

### Self Checks

- [x] I have read the [Contributing Guide](https://github.com/langgenius/dify/blob/main/CONTRIBUTING.md) and [Language Policy](https://github.com/langgenius/dify/issues/1542).
- [x] I have searched for existing issues [search for existing issues](https://github.com/langgenius/dify/issues), including closed ones.
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### 1. Is this request related to a challenge you're experiencing? Tell me about your story.

Dify ships 24 UI locales in `web/i18n`. Azerbaijani (az-AZ) is not among them. The console has no Azerbaijani option.

The translation is ready: 37 files under `web/i18n/az-AZ`, 5960 strings, key names and key order identical to `web/i18n/en-US`, `_one` and `_other` plural branches kept. Registration points: `web/i18n-config/languages.ts`, `web/i18n-config/language.ts`, `web/i18n-config/locale-resources/az-AZ.ts`, `web/service/use-plugins.ts`, `web/service/use-triggers.ts`, `web/utils/format.ts` (dayjs locale) and `api/constants/languages.py` (`Asia/Baku`).

### 2. Additional context or comments

Pull request #42090 carried this change and was closed: the description had no linked issue.

### 3. Can you help us with this feature?

- [x] I am interested in contributing to this feature.

Start by comparing the existing locale registrations with the 37 files under web/i18n/az-AZ and inspect the listed integration points in web/i18n-config, web/service, web/utils/format.ts, and api/constants/languages.py. Done means Azerbaijani is registered consistently, its translations load, the console offers az-AZ, and the Asia/Baku locale behavior is configured.

Written by the indexing model from the issue text.