docs: add docs to CB

Pretty much every class and method should have documentation now.

ref: N25B-295

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

@@ -15,6 +15,14 @@ router = APIRouter()
 # DO NOT LOG INSIDE THIS FUNCTION
 @router.get("/logs/stream")
 async def log_stream():
+    """
+    Server-Sent Events (SSE) endpoint for real-time log streaming.
+
+    Subscribes to the internal ZMQ logging topic and forwards log records to the client.
+    Allows the frontend to display live logs from the backend.
+
+    :return: A StreamingResponse yielding SSE data.
+    """
     context = Context.instance()
     socket = context.socket(zmq.SUB)