Migrates 8 trunk sites (4 online + 4 target) from sgemm_f32 + launch_add_bias_f32_raw pairs to the new sgemm_f32_fused_bias helper. Covers all four GRN Linear layers per encoder: h_s1 Linear_a, h_s1 Linear_b, h_s2 Linear_a, h_s2 Linear_b. Linear_residual has no bias term and stays a plain sgemm_f32_ldb. Drops 8 standalone add_bias_f32 kernel launches + 8 memory round-trips per (online + target) forward step.