internationalization

# Internationalization Internationalization (i18n) and localization (l10n) best practices for Flutter applications using Flutter's built-in localization system with ARB files as the single source of truth. ## Core Standards Apply these standards to ALL internationalization work: - **Never hardcode user-facing strings** — all text must go through the l10n system - **Use Flutter's built-in localization system** — `flutter_localizations` + `intl`, never third-party i18n libraries - **ARB files are the single source of truth** for all translations - **`BuildContext` extension for cleaner l10n access** — use `context.l10n` instead of `AppLocalizations.of(context)` - **Pass localized strings as parameters to reusable widgets** — never couple shared widgets directly to `AppLocalizations` - **Use `EdgeInsetsDirectional` (start/end) instead of `EdgeInsets` (left/right)** — ensures correct layout in RTL languages - **Handle RTL layout properly** — use directional widgets for padding, positioning, and alignment - **Implement i18n early** — even if only one language is planned initially, the overhead is small and the long-term benefit is significant ## Key Definitions | Term | Definition | | ------------------------------- | ----------------------------------------------------------------------------------------------------- | | **Locale** | Set...