refactor: ZMQ context and proxy

Use ZMQ's global context instance and setup an XPUB/XSUB proxy intermediary to allow for easier multi-pubs.

close: N25B-217

src/control_backend/api/v1/endpoints/message.py

@@ -1,8 +1,10 @@
 import logging
 
+import zmq
 from fastapi import APIRouter, Request
-from zmq import Socket
+from zmq.asyncio import Context
 
+from control_backend.core.config import settings
 from control_backend.schemas.message import Message
 
 logger = logging.getLogger(__name__)
@@ -17,8 +19,8 @@ async def receive_message(message: Message, request: Request):
     topic = b"message"
     body = message.model_dump_json().encode("utf-8")
 
-    pub_socket: Socket = request.app.state.internal_comm_socket
-
-    pub_socket.send_multipart([topic, body])
+    pub_socket = Context.instance().socket(zmq.PUB)
+    pub_socket.bind(settings.zmq_settings.internal_pub_address)
+    await pub_socket.send_multipart([topic, body])
 
     return {"status": "Message received"}