This commit implements comprehensive timezone and time format customization:
## Backend Changes
- Added timeFormat field ('12h' | '24h') to user preferences JSONB in user entity
- Timezone field already existed in user entity, now actively used
- Backend ready to accept timezone on registration
## Frontend Components (2 new)
- TimeZoneSelector: Dropdown with timezones grouped by region (Americas, Europe, Asia, Pacific, Africa)
* Auto-detect button to detect browser timezone
* Save functionality with success/error feedback
* Integrated into Settings > Preferences section
- TimeFormatSelector: Radio buttons to choose 12h vs 24h format
* Live preview showing current time in selected format
* Save functionality with user feedback
* Integrated into Settings > Preferences section
## Timezone Auto-Detection
- Register function now auto-detects user's timezone via Intl.DateTimeFormat()
- Detected timezone sent to backend during registration
- Timezone stored in user profile for persistent preference
## Enhanced useLocalizedDate Hook
- Added useAuth integration to access user timezone and timeFormat preferences
- Installed and integrated date-fns-tz for timezone conversion
- New format() function with timezone support via useTimezone option
- New formatTime() function respecting user's 12h/24h preference
- New formatDateTime() function combining date, time, and timezone
- All formatting now respects user's:
* Language (existing: en, es, fr, pt-BR, zh-CN)
* Timezone (user-selected or auto-detected)
* Time format (12h with AM/PM or 24h)
## Settings Page Updates
- Added TimeZoneSelector to Preferences card
- Added TimeFormatSelector to Preferences card
- Visual separators (Dividers) between preference sections
- Settings now show: Language | Units | Timezone | Time Format
## Translations
- Enhanced settings.json with timezone and time format keys:
* preferences.timezone, autoDetectTimezone, timezoneUpdated
* preferences.12hour, 24hour, timeFormatUpdated
## User Experience Flow
1. User registers → timezone auto-detected and saved
2. User can change timezone in Settings > Preferences > Time Zone
3. User can change time format in Settings > Preferences > Time Format
4. All dates/times throughout app respect these preferences
5. Changes persist across sessions
Files changed: 10 files
New dependencies: date-fns-tz
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
Implemented comprehensive frontend localization infrastructure supporting
5 languages (English, Spanish, French, Portuguese, Chinese) with measurement
unit preferences (Metric/Imperial). This lays the foundation for international
user support.
**Core Infrastructure:**
- Installed i18next, react-i18next, i18next-browser-languagedetector
- Created I18nProvider component integrated into app layout
- Configured i18next with language detection and localStorage persistence
- Created 35 translation files (5 languages × 7 namespaces)
**Translation Namespaces:**
- common: App-wide UI elements, navigation, actions
- tracking: Activity tracking (feeding, sleep, diaper, milestones)
- ai: AI assistant chat interface
- auth: Authentication flows (login, signup, password reset)
- settings: Settings and preferences
- onboarding: Onboarding flow
- errors: Error messages and validation
**Custom Hooks:**
- useTranslation: Type-safe translation wrapper
- useLocale: Language and measurement system management
- useFormatting: Date, time, number, and unit formatting
**Measurement Unit Support:**
- Created unit conversion utilities (weight, height, temperature, volume)
- Metric: kg, cm, °C, ml
- Imperial: lb, in, °F, oz
- Bidirectional conversion functions
**UI Components:**
- LanguageSelector: Dropdown to change app language
- MeasurementUnitSelector: Toggle between Metric/Imperial
- Integrated both into Settings page Preferences section
**Next Steps (Remaining):**
- Add measurement preferences to backend user schema
- Create onboarding flow with language/measurement selection
- Apply translations to existing components (dashboard, tracking forms)
- Implement multi-language AI responses
- Add professional translations (currently using basic translations)
**File Highlights:**
- lib/i18n/config.ts: i18next configuration
- hooks/useFormatting.ts: Formatting utilities with locale support
- lib/utils/unitConversion.ts: Unit conversion logic
- components/settings/*Selector.tsx: Language and measurement selectors
- locales/*/: Translation files for 5 languages
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
