feat(frontend): Refonte infrastructure formulaires multi-modes

- Support des modes Desktop/Mobile et Édition/Lecture seule
- Refactoring des widgets de formulaire (PersonalInfo, ProfessionalInfo, Presentation, ChildCard)
- Mise à jour des écrans de récapitulatif (ParentStep5, AmStep4)
- Ajout de navigation (Précédent/Soumettre) sur mobile

Closes #78

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/lib/config/app_router.dart

@@ -4,7 +4,6 @@ import 'package:provider/provider.dart';
 
 // Models
 import '../models/user_registration_data.dart';
-import '../models/nanny_registration_data.dart';
 import '../models/am_registration_data.dart';
 
 // Screens
@@ -15,11 +14,6 @@ import '../screens/auth/parent_register_step2_screen.dart';
 import '../screens/auth/parent_register_step3_screen.dart';
 import '../screens/auth/parent_register_step4_screen.dart';
 import '../screens/auth/parent_register_step5_screen.dart';
-import '../screens/auth/nanny_register_step1_screen.dart';
-import '../screens/auth/nanny_register_step2_screen.dart';
-import '../screens/auth/nanny_register_step3_screen.dart';
-import '../screens/auth/nanny_register_step4_screen.dart';
-import '../screens/auth/nanny_register_confirmation_screen.dart';
 import '../screens/auth/am_register_step1_screen.dart';
 import '../screens/auth/am_register_step2_screen.dart';
 import '../screens/auth/am_register_step3_screen.dart';
@@ -33,7 +27,6 @@ import '../screens/unknown_screen.dart';
 // For ShellRoute, creating them here and passing via .value is common.
 
 final userRegistrationDataNotifier = UserRegistrationData();
-final nannyRegistrationDataNotifier = NannyRegistrationData();
 final amRegistrationDataNotifier = AmRegistrationData();
 
 class AppRouter {
@@ -84,44 +77,6 @@ class AppRouter {
             path: '/parent-register-step5',
             builder: (BuildContext context, GoRouterState state) => const ParentRegisterStep5Screen(),
           ),
-          GoRoute(
-            path: '/parent-register-confirmation',
-            builder: (BuildContext context, GoRouterState state) => const NannyRegisterConfirmationScreen(),
-          ),
-        ],
-      ),
-
-      // --- Nanny Registration Flow ---
-       ShellRoute(
-        builder: (context, state, child) {
-          return ChangeNotifierProvider<NannyRegistrationData>.value(
-             value: nannyRegistrationDataNotifier,
-             child: child,
-          );
-        },
-        routes: <RouteBase>[
-          GoRoute(
-            path: '/nanny-register-step1',
-            builder: (BuildContext context, GoRouterState state) => const NannyRegisterStep1Screen(),
-          ),
-          GoRoute(
-            path: '/nanny-register-step2',
-            builder: (BuildContext context, GoRouterState state) => const NannyRegisterStep2Screen(),
-          ),
-          GoRoute(
-            path: '/nanny-register-step3',
-            builder: (BuildContext context, GoRouterState state) => const NannyRegisterStep3Screen(),
-          ),
-          GoRoute(
-            path: '/nanny-register-step4',
-            builder: (BuildContext context, GoRouterState state) => const NannyRegisterStep4Screen(),
-          ),
-           GoRoute(
-            path: '/nanny-register-confirmation',
-            builder: (BuildContext context, GoRouterState state) {
-              return const NannyRegisterConfirmationScreen();
-            },
-          ),
         ],
       ),
 

frontend/lib/config/display_config.dart

@@ -0,0 +1,106 @@
+import 'package:flutter/material.dart';
+
+/// Mode d'affichage d'un formulaire
+enum DisplayMode {
+  /// Mode éditable (formulaire d'inscription)
+  editable,
+  
+  /// Mode lecture seule (récapitulatif)
+  readonly,
+}
+
+/// Configuration d'affichage pour les widgets de formulaire
+class DisplayConfig {
+  /// Mode d'affichage (editable/readonly)
+  final DisplayMode mode;
+  
+  /// Type de layout détecté (mobile/desktop)
+  final LayoutType layoutType;
+
+  const DisplayConfig({
+    required this.mode,
+    required this.layoutType,
+  });
+
+  /// Crée une config à partir du contexte
+  factory DisplayConfig.fromContext(
+    BuildContext context, {
+    DisplayMode mode = DisplayMode.editable,
+  }) {
+    return DisplayConfig(
+      mode: mode,
+      layoutType: LayoutHelper.getLayoutType(context),
+    );
+  }
+
+  /// Est en mode éditable
+  bool get isEditable => mode == DisplayMode.editable;
+  
+  /// Est en mode lecture seule
+  bool get isReadonly => mode == DisplayMode.readonly;
+  
+  /// Est en layout mobile
+  bool get isMobile => layoutType == LayoutType.mobile;
+  
+  /// Est en layout desktop
+  bool get isDesktop => layoutType == LayoutType.desktop;
+  
+  /// Layout vertical (mobile)
+  bool get isVerticalLayout => isMobile;
+  
+  /// Layout horizontal (desktop)
+  bool get isHorizontalLayout => isDesktop;
+}
+
+/// Type de layout
+enum LayoutType {
+  /// Mobile (< 600px) - toujours vertical
+  mobile,
+  
+  /// Desktop/Tablette (≥ 600px) - horizontal
+  desktop,
+}
+
+/// Utilitaires pour la détection de layout
+class LayoutHelper {
+  /// Seuil de largeur pour mobile/desktop (en pixels)
+  static const double mobileBreakpoint = 600.0;
+
+  /// Détermine le type de layout selon la largeur d'écran
+  static LayoutType getLayoutType(BuildContext context) {
+    final width = MediaQuery.of(context).size.width;
+    return width < mobileBreakpoint 
+      ? LayoutType.mobile 
+      : LayoutType.desktop;
+  }
+
+  /// Vérifie si on est sur mobile
+  static bool isMobile(BuildContext context) {
+    return getLayoutType(context) == LayoutType.mobile;
+  }
+
+  /// Vérifie si on est sur desktop
+  static bool isDesktop(BuildContext context) {
+    return getLayoutType(context) == LayoutType.desktop;
+  }
+
+  /// Retourne un espacement adapté au layout
+  static double getSpacing(BuildContext context, {
+    double mobileSpacing = 12.0,
+    double desktopSpacing = 20.0,
+  }) {
+    return isMobile(context) ? mobileSpacing : desktopSpacing;
+  }
+
+  /// Retourne une largeur max adaptée au layout
+  static double getMaxWidth(BuildContext context, {
+    double? mobileMaxWidth,
+    double? desktopMaxWidth,
+  }) {
+    if (isMobile(context)) {
+      return mobileMaxWidth ?? double.infinity;
+    } else {
+      return desktopMaxWidth ?? 1200.0;
+    }
+  }
+}