feat(mobile): Implement Keycloak WebView authentication with HTTP callback

- Replace flutter_appauth with custom WebView implementation to resolve deep link issues
- Add KeycloakWebViewAuthService with integrated WebView for seamless authentication
- Configure Android manifest for HTTP cleartext traffic support
- Add network security config for development environment (192.168.1.11)
- Update Keycloak client to use HTTP callback endpoint (http://192.168.1.11:8080/auth/callback)
- Remove obsolete keycloak_auth_service.dart and temporary scripts
- Clean up dependencies and regenerate injection configuration
- Tested successfully on multiple Android devices (Xiaomi 2201116TG, SM A725F)

BREAKING CHANGE: Authentication flow now uses WebView instead of external browser
- Users will see Keycloak login page within the app instead of browser redirect
- Resolves ERR_CLEARTEXT_NOT_PERMITTED and deep link state management issues
- Maintains full OIDC compliance with PKCE flow and secure token storage

Technical improvements:
- WebView with custom navigation delegate for callback handling
- Automatic token extraction and user info parsing from JWT
- Proper error handling and user feedback
- Consistent authentication state management across app lifecycle

unionflow-mobile-apps/lib/core/auth/models/auth_state.dart

@@ -78,6 +78,9 @@ class AuthState extends Equatable {
   /// Vérifie si l'utilisateur est connecté
   bool get isAuthenticated => status == AuthStatus.authenticated;
 
+  /// Vérifie si l'authentification est en cours de vérification
+  bool get isChecking => status == AuthStatus.checking;
+
   /// Vérifie si la session est valide
   bool get isSessionValid {
     if (!isAuthenticated || expiresAt == null) return false;

unionflow-mobile-apps/lib/core/auth/models/user_info.dart

@@ -7,6 +7,7 @@ class UserInfo extends Equatable {
   final String firstName;
   final String lastName;
   final String role;
+  final List<String>? roles;
   final String? profilePicture;
   final bool isActive;
 
@@ -16,6 +17,7 @@ class UserInfo extends Equatable {
     required this.firstName,
     required this.lastName,
     required this.role,
+    this.roles,
     this.profilePicture,
     required this.isActive,
   });
@@ -35,6 +37,7 @@ class UserInfo extends Equatable {
       firstName: json['firstName'] ?? '',
       lastName: json['lastName'] ?? '',
       role: json['role'] ?? 'membre',
+      roles: json['roles'] != null ? List<String>.from(json['roles']) : null,
       profilePicture: json['profilePicture'],
       isActive: json['isActive'] ?? true,
     );
@@ -47,6 +50,7 @@ class UserInfo extends Equatable {
       'firstName': firstName,
       'lastName': lastName,
       'role': role,
+      'roles': roles,
       'profilePicture': profilePicture,
       'isActive': isActive,
     };
@@ -58,6 +62,7 @@ class UserInfo extends Equatable {
     String? firstName,
     String? lastName,
     String? role,
+    List<String>? roles,
     String? profilePicture,
     bool? isActive,
   }) {
@@ -67,6 +72,7 @@ class UserInfo extends Equatable {
       firstName: firstName ?? this.firstName,
       lastName: lastName ?? this.lastName,
       role: role ?? this.role,
+      roles: roles ?? this.roles,
       profilePicture: profilePicture ?? this.profilePicture,
       isActive: isActive ?? this.isActive,
     );
@@ -79,6 +85,7 @@ class UserInfo extends Equatable {
         firstName,
         lastName,
         role,
+        roles,
         profilePicture,
         isActive,
       ];