feat: Implement centralized error handling with ErrorService; replace print statements with logging in services and blocs

feat: Add ErrorContent widget for displaying error messages in dialogs and bottom sheets
refactor: Update GroupBloc and GroupRepository to utilize ErrorService for error logging
refactor: Enhance user and trip services to log errors using ErrorService
refactor: Clean up debug print statements in GroupContent and related components

lib/data/models/trip.dart

@@ -62,7 +62,6 @@ class Trip {
         // Essayer de parser comme ISO 8601
         return DateTime.parse(dateValue);
       } catch (e) {
-        print('Erreur parsing date string: $dateValue - $e');
         return DateTime.now();
       }
     }
@@ -72,12 +71,9 @@ class Trip {
         // Traiter comme millisecondes
         return DateTime.fromMillisecondsSinceEpoch(dateValue);
       } catch (e) {
-        print('Erreur parsing date int: $dateValue - $e');
         return DateTime.now();
       }
     }
-
-    print('Type de date non supporté: ${dateValue.runtimeType} - $dateValue');
     return DateTime.now();
   }