Internationalization Setup

When preparing a feature for internationalization:

1. Extract all user-facing strings into a translation file or message catalog. Never hardcode display text.
2. Use the project’s i18n library (react-intl, next-intl, i18next, etc.) for string lookups.
3. Handle pluralization, date formatting, and number formatting with locale-aware functions — not string concatenation.
4. Don’t concatenate translated fragments. Full sentences translate better than assembled parts.
5. Allow for text expansion — translations are often 30-50% longer than English.
6. Test with a pseudo-locale or long strings to catch layout issues from text expansion.