/**
 * Packs the running-state (linear color + residual transmittance) into a
 * single RGBA8-packed u32 per group pixel. Composites the user-supplied
 * background under the residual transmittance so the final image carries
 * the chosen `bgR/bgG/bgB/bgA` everywhere the splats didn't fully cover.
 *
 * @returns WGSL source for the finalize compute shader.
 */
declare const finalizeWgsl: () => string;
export { finalizeWgsl };