Hello and welcome to Just Answer. I am a licensed veterinarian and would be happy to answer your questions.
There is nothing harmful or toxic about spaghetti squash, but keep in mind that any food given to Pari that she is not used to can lead to gastric irritation, especially if a large amount is ingested. That being said, it is full of nutrients including vitamins and is a decent source of fiber. I would not suggest feeding her too much as it will fill her up and she may not get enough of the nutrition from her dog food, but a little won't hurt.
I hope that helps. Please let me know if you have any further questions.
If there are onion or garlic easonings in the sauce, it is not good. They can be toxic to some dogs. The addition of the meat means the fat content will be higher as well, so it increases the likelihood of causing her some GI distress. I would avoid it.