feat(i18n): add zh-TW Traditional Chinese locale support

[PeterDaveHello]

GitHub Copilot Pull Request Summary:

This pull request adds full Traditional Chinese (Taiwan) language support (zh-TW) to both the macOS and web apps, including UI strings, locale detection, and language selection. It introduces new translation files for key pages and features, updates locale recognition logic to correctly identify Traditional Chinese variants, and enhances the language selector to display the new language option.

Localization and Internationalization

• Added Traditional Chinese (Taiwan) translations for macOS UI in zh-Hant.lproj/Localizable.strings, covering all major navigation, settings, and feature labels.
• Created new locale files for zh-TW in the web app, including comprehensive translations for common actions (common.js), chat UI (chat.js), channels page (channels.js), and crons page (crons.js). [1] [2] [3] [4]

Locale Detection and Selection

• Updated locale detection logic in i18n.js to recognize and normalize Traditional Chinese variants (zh-TW, zh-HK, zh-Hant, etc.) to zh-TW.
• Expanded the list of supported locales and exposed zh-TW in the language selector.

Language Selector UI

• Added "Chinese (Traditional)" as an option in the language selector for both English and French UI, ensuring users can select Traditional Chinese from the settings. [1] [2]