What is the Sharia ruling on her demanding money after the project loss, and am I obligated to compensate her, knowing that I also lost all my money?

If your friend joined you in the project with the intention of investment and speculation (mudarabah), then you are not liable for any guarantee unless there is negligence or dereliction of duty on your part, because it is not permissible to stipulate a guarantee of capital in mudarabah. However, if you took her money as a loan to invest it, then you must return her money without any increase or decrease, regardless of whether the project made a profit or incurred a loss.