Function reduce_voxel_average_f32_gpu_buffers 

pub fn reduce_voxel_average_f32_gpu_buffers(
    runtime: &WgpuRuntime,
    values: &Buffer,
    segments: &GpuVoxelSegments,
) -> SpatialResult<Vec<f32>>

Averages per-point f32 values using GPU-resident segment buffers.