Function render_pixels 

pub fn render_pixels(
    pixels: Vec<RawPixelData>,
    options: &DensityPlotOptions,
    render_config: &mut RenderConfig,
) -> Result<PlotBytes>

Render pixels to a JPEG image using the Plotters backend

This function handles the complete rendering pipeline:

1. Sets up Plotters chart with axes and mesh
2. Writes pixels directly to the buffer
3. Encodes to JPEG format

Progress reporting is handled via the RenderConfig if provided.