test(backend): parallelize isolated fixtures [CI] [SKIP TESTS]

backend/tests/MoShiro.Backend.Tests/CapabilityTests.cs

@@ -9,8 +9,7 @@ using MoShiro.Backend.Application;
 namespace MoShiro.Backend.Tests;
 
 /// <summary>能力模型（docs/security/access.md 第 3 节）：每个管理端点声明能力；密钥只能拿到自己拥有能力的子集；写蕴含读。</summary>
-[Collection("probe-e2e")]
-public sealed class CapabilityTests
+public sealed class CapabilityTests : IClassFixture<BackendFixture>
 {
     private readonly BackendFixture _backend;