feat(i18n): add Vietnamese language support

[testdev2212]

Issue for this PR

Closes #

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

This PR adds full Vietnamese (vi-VN) language support to the application. It includes the translation of all UI labels, settings, and menu items to improve the user experience for Vietnamese-speaking users.

How did you verify your code works?

"I verified the changes by:

Running the application locally and switching the language settings to Vietnamese.

Checking all UI elements, menus, and labels to ensure the Vietnamese translations are correctly applied and no text overflow issues occur.

Verifying that the language fallback mechanism works properly if a specific string is missing in the Vietnamese translation file."

Screenshots / recordings

If this is a UI change, please include a screenshot or recording.

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR

If you do not follow this template your PR will be automatically rejected.

[github-actions]

The following comment was made by an LLM, it may be inaccurate:

Based on my search, I found that PR #34577 (the current PR) is the only one specifically for Vietnamese language support. The related i18n PRs found are for other languages:

• PR docs: add Persian (fa) docs site localization #34396: Persian (fa) docs site localization
• PR fix(i18n): translate Windows desktop app menu (File/Edit/View/Go) for all locales #34103: Windows desktop app menu translations
• PR feat(i18n): add Indonesian language support #32555: Indonesian language support
• PR feat(ui): full RTL support for Arabic and RTL languages #32247: Arabic RTL language support
• PR fix(app): complete Spanish translations for General settings #32220: Spanish translations

These are related i18n efforts but not duplicates of the Vietnamese language support PR.

No duplicate PRs found

[github-actions]

Thanks for updating your PR! It now meets our contributing guidelines. 👍

[github-actions]

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