refactor: make download and transfer events durable

tests/test_chain_runtime_context.py

@@ -20,6 +20,7 @@ def _context() -> ChainRuntimeContext:
         async_file_cache=Mock(),
         message_queue_factory=Mock(return_value=Mock()),
         module_dispatcher_factory=ModuleInvocationDispatcher,
+        durable_event_writer=Mock(),
     )
 
 
@@ -33,6 +34,7 @@ def test_chain_accepts_explicit_runtime_context() -> None:
     assert chain.pluginmanager is context.plugin_manager
     assert chain.eventmanager is context.event_manager
     assert chain.messagehelper is context.message_helper
+    assert chain.durable_event_writer is context.durable_event_writer
     context.message_queue_factory.assert_called_once_with(chain.run_module)