I think characterizing (1) as a deictic future is dubious. It may be deictic future in the right context:
I know you haven’t decided yet, but I wanted to tell that I don’t mind what you do.
But in another context it may be a ‘generic’ present, signifying the addressee's habitual practice:
Usually I don’t mind what you do, but in this case I think you’re behaving badly.
For a deictic present, however (if I’m understanding the CGEL use of this term—I take it to mean a construction which indicates specifically present action), I think you have to use the progressive construction:
Go right ahead. I don’t mind what you’re doing at all.
Context is everything. (2), for instance, is unambiguous only because the imperative let me know necessarily points to a future action. In another context, who wins may have generic force. For instance, Grantland Rice's famous verse “For when the One Great Scorer comes/ To mark against your name,/ He writes - not that you won or lost -/ But how you played the Game” may be paraphrased
What matters in any contest is not who wins but how the game is played.