Tighten test runtime governance

[jsugg]

Summary

• add tracked working-directory support to TestContext and cover it with unit and contract tests
• move monkeypatch governance into the default contracts lane and expand fixture analysis to catch direct chdir usage
• migrate the recent clawops regressions onto TestContext, including moving the setup runtime-boundaries coverage into the unit CLI suite
• sync testing docs and packaged asset mirrors with the updated authoring rules