[Frontend] Multi-Language Internationalization (i18n) Framework

[blurbeast]

Overview & Background

FlowFi is a global DeFi payment streaming protocol used by international teams and contractors. Providing multi-language support (English, Spanish, French, Chinese, Japanese, Portuguese) significantly lowers onboarding barriers in emerging markets where crypto payroll is heavily adopted.

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Technical Specification & Architecture

1. i18n Architecture:
   • Set up Next.js internationalization routing with next-intl or lightweight translation dictionaries in frontend/src/locales/.
   • Automatic language detection based on browser navigator.language.
2. Supported Locales:
   • English (en, default)
   • Spanish (es)
   • French (fr)
   • Portuguese (pt)
   • Chinese (zh)
   • Japanese (ja)
3. Language Selector Component:
   • Add language switcher dropdown in Navbar and Settings.
   • Format localized dates, numbers, and currency symbols based on active locale.

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Target Files

• frontend/src/locales/en.json
• frontend/src/locales/es.json
• frontend/src/locales/fr.json
• frontend/src/components/LanguageSelector.tsx
• frontend/src/app/layout.tsx

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Acceptance Criteria

• Complete translation dictionary covering Navbar, Dashboard, Stream Wizard, and Settings.
• Language preference persists in user settings.
• Number and date formatting adapt to the selected locale.

[egwujiohaifesinachiperpetual-max]

Please assign
ETA is 4 hours