Add email auth flow and comprehensive unit tests

Auth improvements:
- Add forgot-password, reset-password, signup, verify-email screens
- Enhance login screen with email/password support
- Add deep link handler for auth redirects
- Expand useAuth hook with email auth methods
- Add supabaseAuth utilities for email authentication

New tests:
- Add nutritionLabelExtractor unit tests
- Add photoEventParser unit tests
- Add productRegistry unit tests
- Add E2E jest setup for integration tests
- Update integration test plan with artifacts

Other fixes:
- Fix EmptyState component styling
- Update history screen query handling
- Update config tests for production schema

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: schwaaamp