Preserve explicit model and provider architecture (#30)

frontend/packages/sxchnge_wallet/lib/src/transport/wallet.dart

@@ -53,6 +53,11 @@ class OperationDTO {
   final bool fail;
 }
 
+class ProfileDTO {
+  const ProfileDTO(this.locale);
+  final String locale;
+}
+
 abstract final class WalletMapper {
   static CurrencyAccount account(AccountDTO d) => CurrencyAccount(
     id: d.id,
@@ -85,5 +90,5 @@ abstract final class WalletMapper {
     status: OperationStatus.values.byName(d.status),
     createdAt: d.created,
   );
-  static AccountProfile profile(String locale) => AccountProfile(locale);
+  static AccountProfile profile(ProfileDTO dto) => AccountProfile(dto.locale);
 }