complete MECE request

frontend/pshared/test/payment/request_dto_format_test.dart

@@ -5,6 +5,7 @@ import 'package:test/test.dart';
 import 'package:pshared/api/requests/payment/initiate.dart';
 import 'package:pshared/api/requests/payment/initiate_payments.dart';
 import 'package:pshared/api/requests/payment/quote.dart';
+import 'package:pshared/api/responses/payment/quotation.dart';
 import 'package:pshared/data/dto/money.dart';
 import 'package:pshared/data/dto/payment/endpoint.dart';
 import 'package:pshared/data/dto/payment/intent/payment.dart';
@@ -40,7 +41,7 @@ void main() {
 
     test('quote payment request uses expected backend field names', () {
       final request = QuotePaymentRequest(
-        idempotencyKey: 'idem-1',
+        idempotencyKey: '',
         previewOnly: true,
         intent: const PaymentIntentDTO(
           kind: 'payout',
@@ -60,7 +61,7 @@ void main() {
       final json =
           jsonDecode(jsonEncode(request.toJson())) as Map<String, dynamic>;
 
-      expect(json['idempotencyKey'], equals('idem-1'));
+      expect(json['idempotencyKey'], equals(''));
       expect(json['previewOnly'], isTrue);
       expect(json['intent'], isA<Map<String, dynamic>>());
 
@@ -75,6 +76,34 @@ void main() {
       expect(destination['type'], equals('cardToken'));
     });
 
+    test('quote response parses backend fx quote pricedAtUnixMs', () {
+      final response = PaymentQuoteResponse.fromJson({
+        'accessToken': {'token': 'token', 'expiration': '2026-02-25T00:00:00Z'},
+        'idempotencyKey': 'idem-1',
+        'quote': {
+          'quoteRef': 'q-1',
+          'debitAmount': {'amount': '10', 'currency': 'USDT'},
+          'expectedSettlementAmount': {'amount': '760', 'currency': 'RUB'},
+          'fxQuote': {
+            'quoteRef': 'fx-1',
+            'baseCurrency': 'USDT',
+            'quoteCurrency': 'RUB',
+            'side': 'sell_base_buy_quote',
+            'price': '76',
+            'baseAmount': {'amount': '10', 'currency': 'USDT'},
+            'quoteAmount': {'amount': '760', 'currency': 'RUB'},
+            'expiresAtUnixMs': 1771945907749,
+            'pricedAtUnixMs': 1771945907000,
+            'provider': 'binance',
+            'rateRef': 'rate-1',
+            'firm': false,
+          },
+        },
+      });
+
+      expect(response.quote.fxQuote?.pricedAtUnixMs, equals(1771945907000));
+    });
+
     test('initiate payment by quote keeps expected fields', () {
       final request = InitiatePaymentRequest(
         idempotencyKey: 'idem-2',