BlueDomme what YOU plan re your work is fine but adding your friend into the equation is making the situation illegal before you even start.
I know you won't be the first to do it, nor the last but if you want to work with peace of mind, and that is needed when prossying , then you are best being the only one working from your apartment.
There are two reasons for that, firstly two girls working from one apartment whether on same day or different days constitutes a brothel and this is breaking the law and it also gives the police the right to enter your premises AT ANY TIME and when they do this they confiscate all laptops, mobile phones, money and IT IS THE PERSON WHO IS ON THE RENT BOOK AS TENANT that gets charged.
So for more than one reason I would not let my friend work from my place. Her work alone, with shorter bookings, though that doesn't ALWAYS mean more bookings, especially in this age, will draw more attention than anything and it could be YOU that ends up homeless

Sorry to be so blunt but there is no sense lying and say everything will be ok. I am saying this before you move in and get stuck by not wanting to offend friend. Best to offend before she starts working from your place. She really should find a place of her own and then you are both working legally.
You don't know what your neighbours are like so it's best to tread carefully until YOU have been working there for a while.
In conclusion, I know you want to help your friend but HER SITUATION IS NOT YOUR PROBLEM.
Please be careful re what you get yourself in to as it may be harder to get yourself out of and would she put you up if you got made homeless if/when you get dawbed in to the police.
Think carefully before you go any further with friend. Don't just take my word for it, others will be along soon to re iterate what I've just said.
I hate to say it too, but when it's not your friends place she will not be so careful re discretion as you.
Be careful.