fix: preserve exploration demonstration source and recording scope

tests/unit/test_prompt_efficiency.py

@@ -91,6 +91,7 @@ def test_assistant_message_count_does_not_change_exploration_context(monkeypatch
         get=lambda _: session, recent_messages=lambda *a, **k: history, case=lambda _: None
     )
     monkeypatch.setattr("artemis.exploration.runtime.explorations", store)
+    monkeypatch.setattr("artemis.exploration.demonstrations.Demonstrations.list", lambda *a: [])
     monkeypatch.setattr("artemis.exploration.editorial.prior_context", lambda *a, **k: [])
     ctx = SimpleNamespace(exploration_id="explore", exploration_run_id="run")
     first = conversation_message(ctx).content