Перевести задачи Discovery на NotFoundException

DiscoveryTasksService (get/patch/delete/start/pause) бросает NotFoundException вместо null; эндпоинты отдают 404 через общий обработчик.

src/core/tests/Deal.Tests.Unit/Modules/Discovery/DiscoveryTasksServiceTests.cs

@@ -1,8 +1,9 @@
 using Deal.Modules.Discovery.Application.Exceptions;
 using Deal.Modules.Discovery.Application.Models;
-using Deal.Tests.Unit.Support;
 using Deal.Modules.Discovery.Application.Services;
+using Deal.SharedKernel.Errors;
 using Deal.Tests.Unit.Modules.Settings;
+using Deal.Tests.Unit.Support;
 
 namespace Deal.Tests.Unit.Modules.Discovery;
 
@@ -131,14 +132,13 @@ public sealed class DiscoveryTasksServiceTests
     }
 
     [Fact]
-    public async Task Patch_MissingTask_ReturnsNull()
+    public async Task Patch_MissingTask_ThrowsNotFound()
     {
         (DiscoveryTasksService service, _, _) = Create();
 
-        DiscoveryTaskDto? patched = await service.PatchAsync(
-            "dt_missing", new DiscoveryTaskPatch { Name = "Новое" }, CancellationToken.None);
-
-        Assert.Null(patched);
+        await Assert.ThrowsAsync<NotFoundException>(
+            () => service.PatchAsync(
+                "dt_missing", new DiscoveryTaskPatch { Name = "Новое" }, CancellationToken.None));
     }
 
     [Fact]
@@ -201,13 +201,12 @@ public sealed class DiscoveryTasksServiceTests
     }
 
     [Fact]
-    public async Task Start_MissingTask_ReturnsNull()
+    public async Task Start_MissingTask_ThrowsNotFound()
     {
         (DiscoveryTasksService service, _, _) = Create();
 
-        DiscoveryTaskDto? task = await service.StartAsync("dt_missing", CancellationToken.None);
-
-        Assert.Null(task);
+        await Assert.ThrowsAsync<NotFoundException>(
+            () => service.StartAsync("dt_missing", CancellationToken.None));
     }
 
     [Fact]
@@ -281,9 +280,8 @@ public sealed class DiscoveryTasksServiceTests
         store.SeedCandidate(Candidate("c_2", "dt_2"));
         await store.Store.UpsertBlacklistAsync("c_1", "Источник", "причина", CancellationToken.None);
 
-        bool deleted = await service.DeleteAsync("dt_1", CancellationToken.None);
+        await service.DeleteAsync("dt_1", CancellationToken.None);
 
-        Assert.True(deleted);
         Assert.Single(store.Tasks); // dt_2 осталась
         Assert.Equal("dt_2", Assert.Single(store.Tasks).Id);
         Assert.Single(store.Candidates); // кандидат dt_2 остался
@@ -292,13 +290,12 @@ public sealed class DiscoveryTasksServiceTests
     }
 
     [Fact]
-    public async Task Delete_MissingTask_ReturnsFalse()
+    public async Task Delete_MissingTask_ThrowsNotFound()
     {
         (DiscoveryTasksService service, _, _) = Create();
 
-        bool deleted = await service.DeleteAsync("dt_missing", CancellationToken.None);
-
-        Assert.False(deleted);
+        await Assert.ThrowsAsync<NotFoundException>(
+            () => service.DeleteAsync("dt_missing", CancellationToken.None));
     }
 
     [Fact]