test(backend): cover step 17 modules and extract stubs

Add tests for partnership workflow, middleman adaptation and idea notifications; extract reusable test stubs into separate files; add architecture guard forbidding object-valued dictionaries in data contracts.

tests/TarninaHub.Tests/Controllers/SubmissionsControllerTests.cs

@@ -5,6 +5,7 @@ using TarninaHub.Application.Abstractions;
 using TarninaHub.Application.Dtos;
 using TarninaHub.Controllers;
 using TarninaHub.Tests.Matchmaking;
+using TarninaHub.Tests.Stubs;
 
 namespace TarninaHub.Tests.Controllers;
 
@@ -12,7 +13,10 @@ public class SubmissionsControllerTests
 {
     private static SubmissionsController CreateController(ISubmissionService service, string role = "operator")
     {
-        var controller = new SubmissionsController(service, new StubMatchmakingService());
+        var controller = new SubmissionsController(
+            service,
+            new StubMatchmakingService(),
+            new StubNotificationService());
         var identity = new ClaimsIdentity(
             [new Claim("sub", "user:tester"), new Claim("role", role)],
             authenticationType: "test");
@@ -81,40 +85,4 @@ public class SubmissionsControllerTests
 
         Assert.IsType<NotFoundResult>(result.Result);
     }
-
-    private sealed class StubSubmissionService : ISubmissionService
-    {
-        public SubmissionResponse? Current { get; set; }
-
-        public SubmissionResponse? UpdateResult { get; set; }
-
-        public string? LastRequestedStatus { get; private set; }
-
-        public Task<SubmissionResponse> CreateAsync(
-            string authorId,
-            CreateSubmissionRequest request,
-            CancellationToken cancellationToken) => Task.FromResult(SampleSubmission("new"));
-
-        public Task<PagedResponse<SubmissionResponse>> ListAsync(
-            string viewerId,
-            bool isStaff,
-            string? status,
-            int page,
-            int pageSize,
-            CancellationToken cancellationToken) => Task.FromResult(
-                new PagedResponse<SubmissionResponse>([], page, pageSize, 0));
-
-        public Task<SubmissionResponse?> GetAsync(string submissionId, CancellationToken cancellationToken) =>
-            Task.FromResult(Current);
-
-        public Task<SubmissionResponse?> UpdateStatusAsync(
-            string submissionId,
-            string newStatus,
-            CancellationToken cancellationToken)
-        {
-            LastRequestedStatus = newStatus;
-
-            return Task.FromResult(UpdateResult);
-        }
-    }
 }