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/command.py

@@ -1,9 +1,11 @@
-from fastapi import APIRouter, Request
 import logging
 
-from zmq import Socket
+import zmq
+from fastapi import APIRouter, Request
+from zmq.asyncio import Context
 
-from control_backend.schemas.ri_message import SpeechCommand, RIEndpoint
+from control_backend.core.config import settings
+from control_backend.schemas.ri_message import SpeechCommand
 
 logger = logging.getLogger(__name__)
 
@@ -15,8 +17,8 @@ async def receive_command(command: SpeechCommand, request: Request):
     # Validate and retrieve data.
     SpeechCommand.model_validate(command)
     topic = b"command"
-    pub_socket: Socket = request.app.state.internal_comm_socket
-    pub_socket.send_multipart([topic, command.model_dump_json().encode()])
-    
+    pub_socket = Context.instance().socket(zmq.PUB)
+    pub_socket.connect(settings.zmq_settings.internal_pub_address)
+    await pub_socket.send_multipart([topic, command.model_dump_json().encode()])
 
     return {"status": "Command received"}