For anyone wondering about the localisation of 'Fuck you', that's been done since you can omit the subject in Japanese.
She could be saying 'Fuck' by its lonesome, but given the context, it's more likely directly pointed at Rudy in this case.
The 'nano' suffix to the 'fakku' in the WN TL is just a characterisation thing that doesn't TL well.
I haven't gotten round to reading the novels, but I'll likely aim to TL where the 'Fuck' is directed towards based on the context in each instance.