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';

frontend/src/pages/onboarding/OnboardingPage.tsx

@@ -1,10 +1,10 @@
 import React from 'react';
-import { OnboardingWizard } from '../../components/domain/onboarding';
+import { UnifiedOnboardingWizard } from '../../components/domain/onboarding';
 import { PublicLayout } from '../../components/layout';
 
 const OnboardingPage: React.FC = () => {
   return (
-    <PublicLayout 
+    <PublicLayout
       variant="full-width"
       maxWidth="full"
       headerProps={{
@@ -16,7 +16,7 @@ const OnboardingPage: React.FC = () => {
     >
       <div className="min-h-screen bg-[var(--bg-primary)] py-8">
         <div className="container mx-auto px-4">
-          <OnboardingWizard />
+          <UnifiedOnboardingWizard />
         </div>
       </div>
     </PublicLayout>