test: 隔离单测中的站点原生资源 (#6452)

* test: isolate native site resources

* refactor(test): retain sites stub helper contract

* fix(test): preserve sites stub probe imports

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Co-authored-by: jxxghp <jxxghp@gmail.com>

tests/fixtures/architecture/dependency-baseline.json

@@ -6471,7 +6471,6 @@
     "app.testing -> app.testing.stub",
     "app.testing.bootstrap -> app.application",
     "app.testing.bootstrap -> app.application.service",
-    "app.testing.bootstrap -> app.application.site",
     "app.testing.bootstrap -> app.db",
     "app.testing.bootstrap -> app.db.adapters",
     "app.testing.bootstrap -> app.db.adapters.transaction",