feat: add Vietnamese language support and update language switcher

[phamdohung161]

Summary

• Add full Vietnamese locale under packages/web/src/locales/vi/ (common, game, errors, manager, quizz)
• Register vi in LanguageSwitcher
• Add language.vi label to all existing common.json locales (en/de/es/fr/it/ja/vi)

Context

Razzia already supports multiple languages via i18next + locale JSON. This MR adds Vietnamese so users can select VI in the language switcher without changing i18n bootstrap (locales are loaded via glob).

[phamdohung161]

Hi @Ralex91, After adding the vi locale, two small fixes came up while testing the Vietnamese UI / long strings:

1. Rank translation key (Result.tsx)
   The fallback for ranks outside the top 3 used the wrong namespace (rank.other), so the translation did not resolve. Updated to game:rank.other to match the game namespace.
2. Text wrapping (AnswerButton.tsx, Room.tsx)
   Replaced break-all with break-word for answer text and room URLs to avoid mid-word / awkward breaks on long strings.