feat: enforce tenant isolation and shared question bank

Tiku.IntegrationTests/Api/QuestionBankEndpointTests.cs

@@ -97,11 +97,17 @@ public sealed class QuestionBankEndpointTests
                 VersionNo = 2,
                 Content = "题干关键词"
             });
+        var questionReference = await factory.SeedQuestionReferenceAsync(
+            tenantId,
+            tenantId,
+            includedQuestionId);
         await factory.SeedAsync(new QuestionCollectionItem
         {
             Id = Guid.NewGuid(),
             TenantId = tenantId,
             CollectionId = collectionId,
+            QuestionReferenceId = questionReference.Id,
+            QuestionOwnerTenantId = tenantId,
             QuestionId = includedQuestionId
         });
         using var client = factory.CreateClient();