test: verify portable workspace registry end to end

harness/tests/test_session_documents.py

@@ -291,6 +291,10 @@ def test_cli_documents_json(tmp_path, monkeypatch):
     m = create_session("q", _db(), tmp_path)
     from tht.cli import session_cmd
 
+    # The CLI resolves its local principal through THT_HOME. Keep this test hermetic instead
+    # of changing the developer's real identity directory while exercising JSON output.
+    monkeypatch.setenv("THT_HOME", str(tmp_path / "thoth-home"))
+
     class FakePaths:
         sessions = tmp_path