New ops: CumSum, Sort, Argsort, Greater, MaxAxis — all bound to mlx-c.
TopP (nucleus) sampling now fully implemented: sorts probabilities
descending, computes cumulative sum, masks tokens beyond the threshold,
and scatters the mask back to original positions via argsort.
MinP sampling now fully implemented: computes softmax, finds max
probability, masks tokens below min_p * max_prob.
Both were previously stubs that passed through logits unchanged.
10 new tests (CumSum variants, Sort, Argsort, Greater, MaxAxis,
TopP, MinP). 176 total tests passing.
Co-Authored-By: Virgil <virgil@lethean.io>
f39126f6bd