I'm sorry to read this, congratulations however on your daughter.
I worked with a woman who's daughter was also the product of rape and her husband couldn't love the baby and told her during a very awful argument with her when she was a teenager, it really fucked her up for a while but... she DID get over it. Took therapy etc but she was able to have a wonderful adulthood even with this knowledge.
My first thought is, never let her know, however logically, if she ever decides to do some kind of ancestry dna thing as an adult, it leaves her at risk of contacting him unbeknownst to you.
I'd tell her once she reaches adulthood for her own safety, but that would be the only purpose of it.
I'd definitely seek professional advice and more than one opinion to be honest, see which advice you feel will suit your daughter the most, it is a horrid thing to know.
( I wouldn't really recommend lying either, even though that seems the best option, its easy to get caught in lies)
I'm so sorry this is the situation you've brought your beautiful daughter into, but you've been extremely strong and no doubt you will be amazing ❤