Timezone:
- Add diligence/utils/dates.py with today_for_user(), now_for_user(), day_start_utc()
- Replace all 20 date.today() calls across 10 files with timezone-aware helpers
- Remove hardcoded Asia/Bangkok offset hack in nutrition router
- Change defaults from Asia/Bangkok to UTC in user model, nutrition model, config
- Add timezone field to RegisterRequest schema
- Set user.timezone from browser detection during registration
- Frontend sends Intl.DateTimeFormat().resolvedOptions().timeZone on register
Branding:
- Login page: Fitness Rewards -> Diligence, updated tagline and emoji
- index.html title: Fitness Rewards -> Diligence
Frontend rebuild:
- Fresh Vite build with all changes (index-CsKoBN0D.js)
- Nav bar, timezone detection, and branding all verified in built bundle
