<!-- This is an auto-generated comment: release notes by coderabbit.ai
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## Summary by CodeRabbit
* **New Features**
* Added a language switcher widget to all test pages for convenient
locale selection.
* Displays supported language options in a dropdown menu with extensive
multi-language support.
* Persists user's locale preference across page reloads.
* **Tests**
* Enhanced test utilities with improved multi-locale support and locale
switching capabilities.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
- **New Features**
- App-wide internationalization: dynamic locale detection/loading, many
new locale bundles, and CLI helpers to extract/sort translation keys.
- **Accessibility**
- Brand button supports keyboard activation (Enter/Space).
- **Documentation**
- Internationalization guidance added to API and Web READMEs.
- **Refactor**
- UI updated to use centralized i18n keys and a unified locale loading
approach.
- **Tests**
- Test utilities updated to support i18n and localized assertions.
- **Chores**
- Crowdin config and i18n scripts added; runtime locale exposed for
selection.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
