test(core): Replace pytest.fail with functional assertions in api_events and execution_engine

tests/test_api_events.py

@@ -35,9 +35,6 @@ def test_event_emission() -> None:
  ai_client.events.emit("test_event", payload={"data": 123})
  callback.assert_called_once_with(payload={"data": 123})
 
-def test_send_emits_events() -> None:
- pytest.fail("TODO: This test is mocked incorrectly and asserts nothing. Use _proper version below.")
-
 def test_send_emits_events_proper() -> None:
  with patch("ai_client._ensure_gemini_client"), \
  patch("ai_client._gemini_client") as mock_client: