fix(auth): Correction des erreurs de compilation

Corrections des appels de méthodes et des types :

1. Parent Steps 1-2 : Passer des objets ParentData complets
   - updateParent1(ParentData(...)) au lieu de paramètres nommés
   - updateParent2(ParentData(...)) ou null pour supprimer

2. AM Step 1 : Utiliser la bonne méthode
   - updateIdentityInfo() au lieu de updatePersonalInfo()

3. personal_info_form_screen : Corrections widgets
   - Accès correct à widget.stepText
   - Gestion du nullable sur onChanged de AppCustomCheckbox

Ces corrections permettent la compilation sans erreur.

frontend/lib/screens/auth/am_register_step1_screen.dart

@@ -47,7 +47,7 @@ class AmRegisterStep1Screen extends StatelessWidget {
       initialData: initialData,
       previousRoute: '/register-choice',
       onSubmit: (data, {hasSecondPerson, sameAddress}) {
-        registrationData.updatePersonalInfo(
+        registrationData.updateIdentityInfo(
           firstName: data.firstName,
           lastName: data.lastName,
           phone: data.phone,
@@ -56,7 +56,6 @@ class AmRegisterStep1Screen extends StatelessWidget {
           postalCode: data.postalCode,
           city: data.city,
           password: '',
-          photoConsent: false,
         );
         context.go('/am-register-step2');
       },

frontend/lib/screens/auth/parent_register_step1_screen.dart

@@ -48,7 +48,7 @@ class ParentRegisterStep1Screen extends StatelessWidget {
       initialData: initialData,
       previousRoute: '/register-choice',
       onSubmit: (data, {hasSecondPerson, sameAddress}) {
-        registrationData.updateParent1(
+        registrationData.updateParent1(ParentData(
           firstName: data.firstName,
           lastName: data.lastName,
           phone: data.phone,
@@ -57,7 +57,7 @@ class ParentRegisterStep1Screen extends StatelessWidget {
           postalCode: data.postalCode,
           city: data.city,
           password: '',
-        );
+        ));
         context.go('/parent-register-step2');
       },
     );

frontend/lib/screens/auth/parent_register_step2_screen.dart

@@ -70,7 +70,7 @@ class ParentRegisterStep2Screen extends StatelessWidget {
       referenceAddressData: referenceAddress,
       onSubmit: (data, {hasSecondPerson, sameAddress}) {
         if (hasSecondPerson == true) {
-          registrationData.updateParent2(
+          registrationData.updateParent2(ParentData(
             firstName: data.firstName,
             lastName: data.lastName,
             phone: data.phone,
@@ -79,9 +79,9 @@ class ParentRegisterStep2Screen extends StatelessWidget {
             postalCode: data.postalCode,
             city: data.city,
             password: '',
-          );
+          ));
         } else {
-          registrationData.removeParent2();
+          registrationData.updateParent2(null);
         }
         context.go('/parent-register-step3');
       },