Drill small holes at the top of the cabinet to install the window blinds. Remember to drill holes that are a bit smaller than the screw you will use. Make sure that you can open and close the blinds after they are installed.
I chose to install the blinds on the front of the cabinet, but you could also install them just inside if the shelves are recessed so that the blinds can clear them.
We'll assume you're ok with this, but you can opt-out if you wish.