Function apply_expert_lora_sorted 

pub fn apply_expert_lora_sorted(
    gpu: &dyn GpuBackend,
    kernels: &LoraKernels,
    layer: &ExpertLoraLayer,
    proj: ExpertProj,
    expert_offsets_host: &[u32],
    x: DevicePtr,
    base_out: DevicePtr,
    max_rows: u32,
    lora_xa: DevicePtr,
    lora_delta: DevicePtr,
    stream: u64,
) -> Result<()>

2026-09-25: Fold proj’s per-expert deltas onto the expert-sorted grouped-GEMM output. x is the sorted input ([total_expanded, k_in]), base_out the sorted output ([total_expanded, n_out], in place), and expert_offsets_host a host copy of expert_offsets. Only experts with a pair for proj and at least one row are folded, each over its own row block.