Перевести FakeSettingsStore на NSubstitute (42 файла потребителей)

Хелпер Support/TestSettingsStore: словарь настроек, GetAsync/GetAllAsync/SetAsync/
RemoveAsync читают состояние на момент вызова (GetAllAsync — ленивый, ключ для
снапшот-сервисов). DI получает .Store, тесты сохраняют Preload/GetStoredJson.

src/core/tests/Deal.Tests.Unit/Contracts/GrpcMlClientTests.cs

@@ -110,7 +110,7 @@ public sealed class GrpcMlClientTests
                 Eval = new ModelEval { Count = 5, Correct = 4, Accuracy = 0.8 },
             };
 
-            var settings = new FakeSettingsStore();
+            var settings = new TestSettingsStore();
             settings.Preload(SettingsKeys.MlDecisions, "7");
             settings.Preload(SettingsKeys.AiDecisions, "3");
             var learning = new FakeMlLearningStore { LearningCount = 9 };
@@ -309,21 +309,22 @@ public sealed class GrpcMlClientTests
     // Возвращает: Экземпляр GrpcMlClient в tenant-контексте теста.
     private static GrpcMlClient CreateClient(
         int port,
-        FakeSettingsStore? settings = null,
+        TestSettingsStore? settings = null,
         FakeMlLearningStore? learning = null,
         MlStatusCache? cache = null)
     {
+        settings ??= new TestSettingsStore();
         ITenantContext tenantContext = new TenantContext();
         tenantContext.SetTenant(new TenantId(TenantIdValue));
         var options = new MlServiceOptions { UseLocal = false, Endpoint = $"http://127.0.0.1:{port}" };
         return new GrpcMlClient(
             tenantContext,
-            settings ?? new FakeSettingsStore(),
+            settings.Store,
             learning ?? new FakeMlLearningStore(),
             new MlGrpcConnection(options),
             cache ?? new MlStatusCache(),
             new TokenUsageRecorder(
-                settings ?? new FakeSettingsStore(),
+                settings.Store,
                 new TestTenantLimitStore().Store,
                 tenantContext,
                 new TokenUsageEventService(new TestTokenUsageEventStore().Store)),