Function resize_pack_chw 

pub fn resize_pack_chw(
    input: ImageView<'_, u8, 3>,
    output_width: usize,
    output_height: usize,
    scale: f32,
    mean: [f32; 3],
    std: [f32; 3],
) -> Result<PlanarImage<f32, 3>, VisionError>

Fuses bilinear RGB resize, normalization, and CHW packing without an intermediate image.