feat: integrate ErrorService for consistent error display and standardize bloc error messages.

lib/blocs/expense/expense_bloc.dart

@@ -72,7 +72,7 @@ class ExpenseBloc extends Bloc<ExpenseEvent, ExpenseState> {
           );
     } catch (e) {
       _errorService.logError('ExpenseBloc', 'Error loading expenses: $e');
-      emit(ExpenseError(e.toString()));
+      emit(const ExpenseError('Impossible de charger les dépenses'));
     }
   }
 
@@ -116,7 +116,7 @@ class ExpenseBloc extends Bloc<ExpenseEvent, ExpenseState> {
       emit(const ExpenseOperationSuccess('Expense created successfully'));
     } catch (e) {
       _errorService.logError('ExpenseBloc', 'Error creating expense: $e');
-      emit(ExpenseError(e.toString()));
+      emit(const ExpenseError('Impossible de créer la dépense'));
     }
   }
 
@@ -141,7 +141,7 @@ class ExpenseBloc extends Bloc<ExpenseEvent, ExpenseState> {
       emit(const ExpenseOperationSuccess('Expense updated successfully'));
     } catch (e) {
       _errorService.logError('ExpenseBloc', 'Error updating expense: $e');
-      emit(ExpenseError(e.toString()));
+      emit(const ExpenseError('Impossible de mettre à jour la dépense'));
     }
   }
 
@@ -162,7 +162,7 @@ class ExpenseBloc extends Bloc<ExpenseEvent, ExpenseState> {
       emit(const ExpenseOperationSuccess('Expense deleted successfully'));
     } catch (e) {
       _errorService.logError('ExpenseBloc', 'Error deleting expense: $e');
-      emit(ExpenseError(e.toString()));
+      emit(const ExpenseError('Impossible de supprimer la dépense'));
     }
   }
 
@@ -184,7 +184,7 @@ class ExpenseBloc extends Bloc<ExpenseEvent, ExpenseState> {
       emit(const ExpenseOperationSuccess('Payment marked as completed'));
     } catch (e) {
       _errorService.logError('ExpenseBloc', 'Error marking split as paid: $e');
-      emit(ExpenseError(e.toString()));
+      emit(const ExpenseError('Impossible de marquer comme payé'));
     }
   }
 
@@ -206,7 +206,7 @@ class ExpenseBloc extends Bloc<ExpenseEvent, ExpenseState> {
       emit(const ExpenseOperationSuccess('Expense archived successfully'));
     } catch (e) {
       _errorService.logError('ExpenseBloc', 'Error archiving expense: $e');
-      emit(ExpenseError(e.toString()));
+      emit(const ExpenseError('Impossible d\'archiver la dépense'));
     }
   }