feat: Implement multi-step registration for Childminder with data validation and summary display

- Added routes for registration steps 2, 3, and 4 in app_router.dart.
- Created AmRegisterStep2Screen for entering professional details including birth date, city, country, social security number, agreement number, and max children.
- Implemented validation for social security number and max children fields.
- Developed AmRegisterStep3Screen for entering a motivation message and accepting terms and conditions.
- Created AmRegisterStep4Screen to display a summary of the registration data for review before submission.
- Introduced SummaryCard widget for displaying user information in a structured format.
- Enhanced DataGenerator utility to provide realistic data for testing.

frontend/lib/screens/auth/parent/parent_register_step5_screen.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:google_fonts/google_fonts.dart';
+import 'package:p_tits_pas/widgets/Summary.dart';
 import '../../../models/parent_user_registration_data.dart'; // Utilisation du vrai modèle
 import '../../../widgets/image_button.dart'; // Import du ImageButton
 import '../../../models/card_assets.dart'; // Import des enums de cartes
@@ -127,7 +128,7 @@ class ParentRegisterStep5Screen extends StatelessWidget {
       const SizedBox(height: verticalSpacing),
       _buildDisplayFieldValue(context, "Adresse:", "${data.address}\n${data.postalCode} ${data.city}".trim(), multiLine: true, fieldHeight: 80, labelFontSize: labelFontSize),
     ];
-    return _SummaryCard(
+    return SummaryCard(
       backgroundImagePath: CardColorHorizontal.blue.path,
       title: 'Deuxième Parent',
       content: details,