Preserve explicit model and provider architecture (#30)

frontend/packages/sxchnge_wallet/lib/src/services/dummy.dart

@@ -204,7 +204,7 @@ class DummyWalletService implements WalletService {
   @override
   Future<AccountProfile> profile() async {
     await _wait();
-    return WalletMapper.profile(_locale);
+    return WalletMapper.profile(ProfileDTO(_locale));
   }
 
   @override
@@ -213,7 +213,7 @@ class DummyWalletService implements WalletService {
     if (!['en', 'ru'].contains(locale))
       throw const WalletException(WalletError.unsupported);
     _locale = locale;
-    return WalletMapper.profile(_locale);
+    return WalletMapper.profile(ProfileDTO(_locale));
   }
 
   // Kept separate from wallet fetch because LimitsService has a different result.

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);
 }