Stabilize frontend login. Make chat messages multiline.

backend/server.py

@@ -86,6 +86,10 @@ def start_server(app):
                 await websocket.send(json.dumps({'error': 'invalid credentials'}))
                 return
 
+        # TODO: print username instead, same in the finally block
+        print("User logged in:", user_id) 
+        await websocket.send(json.dumps({'message': 'authentication successful'}))
+
         send_queue = asyncio.Queue()
         async def sender_task():
             nonlocal send_queue
@@ -190,6 +194,7 @@ def start_server(app):
                 else:
                     await send({'error': 'unknown action: ' + action, 'nonce': nonce})
         finally:
+            print("User logged out:", user_id)
             app.remove_user_connection(user_id, send_queue)
 
     server.run(debug=True)