delete old interop, turn on with placeholders, add py312 and py313 to CI testing

tests/conftest.py

@@ -1,23 +1,6 @@
 import pytest
 
-from tests.utils.factories import (
-    HostFactory,
-)
-
 
 @pytest.fixture
 def security_protocol():
     return None
-
-
-@pytest.fixture
-def num_hosts():
-    return 3
-
-
-@pytest.fixture
-async def hosts(num_hosts, security_protocol, nursery):
-    async with HostFactory.create_batch_and_listen(
-        num_hosts, security_protocol=security_protocol
-    ) as _hosts:
-        yield _hosts