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/features/members/presentation/bloc/membres_event.dart

@@ -29,6 +29,16 @@ class SearchMembres extends MembresEvent {
   List<Object?> get props => [query];
 }
 
+/// Événement pour recherche avancée des membres avec filtres multiples
+class AdvancedSearchMembres extends MembresEvent {
+  const AdvancedSearchMembres(this.filters);
+
+  final Map<String, dynamic> filters;
+
+  @override
+  List<Object?> get props => [filters];
+}
+
 /// Événement pour charger un membre spécifique
 class LoadMembreById extends MembresEvent {
   const LoadMembreById(this.id);