Validation scope: the clean Blender builder exports only four material-group mesh nodes. The GLB is audited for finite attributes, degenerate faces, embedded image dimensions, budgets and PBR maps. Forge browse/stage.mjs makeLoader and makeStudio load the actual binary in Chromium WebGL; hero, rear and close-up captures are inspected. Software WebGL validates loading and appearance, not hardware frame-rate performance.
Final runtime correction: removed thin salt-crust overlay meshes whose irregular cutouts read as jagged floating edges in the exported close-up; increased shell normal smoothing. The true arch silhouette and baked sea-glass, bronze, mossy stone and shell materials remain.