Replace old onboarding with UnifiedOnboardingWizard

- Updated OnboardingPage to use UnifiedOnboardingWizard instead of old OnboardingWizard
- Added UnifiedOnboardingWizard export to onboarding index
- New onboarding now fully functional after registration

The new unified onboarding provides a comprehensive setup flow:
✓ Bakery type selection (production/retail/mixed)
✓ Data source choice (AI-assisted vs manual)
✓ Tenant registration
✓ AI-assisted path with categorization and stock entry
✓ Manual path with all setup steps
✓ Suppliers, inventory, recipes, processes setup
✓ Quality and team configuration
✓ ML training
✓ Completion and tour launch

This replaces the old 4-step onboarding with a complete, contextual flow that adapts based on user choices.

frontend/src/components/domain/onboarding/index.ts

@@ -1 +1,2 @@
-export { OnboardingWizard } from './OnboardingWizard';
+export { OnboardingWizard } from './OnboardingWizard';
+export { UnifiedOnboardingWizard } from './UnifiedOnboardingWizard';