Function enc_gemm3_sk_f16a_src 

pub fn enc_gemm3_sk_f16a_src(bm: usize, bn: usize, bk: usize) -> String

The f16-ARITHMETIC split-K partial: the same patch over enc_gemm3_f16a_src — its epilogue already stores f32(acc), so the partials stay f32 and the SAME reduce kernel serves both precisions.