feat: customer page

lib/domain/customer/failures/customer_failure.dart

@@ -0,0 +1,10 @@
+part of '../customer.dart';
+
+@freezed
+sealed class CustomerFailure with _$CustomerFailure {
+  const factory CustomerFailure.serverError(ApiFailure failure) = _ServerError;
+  const factory CustomerFailure.unexpectedError() = _UnexpectedError;
+  const factory CustomerFailure.empty() = _Empty;
+  const factory CustomerFailure.dynamicErrorMessage(String erroMessage) =
+      _DynamicErrorMessage;
+}