feat: add agent that is able to receive messages from UI

Inside the `/message` enpoint we put a message onto the internal event
queue, which gets read by TestAgent. This agent, in turn, logs the
message (temporary behaviour until we implement RI integration).

The name TestAgent is of course temporary, this is just for exploratory
purposes.

ref: N25B-165

src/control_backend/main.py

@@ -3,10 +3,13 @@ import contextlib
 from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
 import logging
+import zmq
 
 # Internal imports
+from control_backend.agents.test_agent import TestAgent
 from control_backend.api.v1.router import api_router
 from control_backend.core.config import settings
+from control_backend.core.zmq_context import context
 
 logger = logging.getLogger(__name__)
 logging.basicConfig(level=logging.INFO)
@@ -14,6 +17,17 @@ logging.basicConfig(level=logging.INFO)
 @contextlib.asynccontextmanager
 async def lifespan(app: FastAPI):
     logger.info("%s starting up.", app.title)
+
+    # Initiate sockets
+    internal_comm_socket = context.socket(zmq.PUB)
+    internal_comm_address = settings.zmq_settings.internal_comm_address
+    internal_comm_socket.bind(internal_comm_address)
+    app.state.internal_comm_socket = internal_comm_socket
+    logger.info("Internal publishing socket bound to %s", internal_comm_socket)
+
+    # Initiate agents
+    test_agent = TestAgent("test_agent@localhost", "test_agent")
+    await test_agent.start()
     
     yield
     
@@ -34,4 +48,4 @@ app.include_router(api_router, prefix="") # TODO: make prefix /api/v1
 
 @app.get("/")
 async def root():
-    return {"status": "ok"}
+    return {"status": "ok"}