Interactive plush watermelon soft-body demo with whimsical motions and sound

GOAL: Make "Plush Watermelon" (Material Studies No. MOTION: 032) on the Plush Penguin WebGPU engine: XPBD soft-body lattice, shell fur, cloth limbs, posture-driven gait, Hand / Finger / Comb tools. Shape (one SDF): - A fat wedge cut from a sphere by two planes through one horizontal axis, about 76° apart. - The axis is the top edge, so each cut face is a semicircle. - The cut faces are slightly puffy and every seam is rounded. - It sits on a small flat patch of its round rind. Regions: - Flesh: long fluffy red minky. - Rind: a white band along the outer edge of both faces. - Skin: green, with dark jagged stripes running pole to pole around the wedge's axis. - Seeds: short-pile felt teardrops pointing in toward the axis, a few on the front face around the face, more on the back. Front face: two bead eyes, rosy cheeks, and an embroidered smile thread laid into a short-pile groove. Limbs: two brown felt legs stuck out in front, and two stubby felt cloth arms at the wedge's ends. Actions: - Toddle: walk on the legs. - Rock: seesaw forward and back on the rind with a synthesized giggle. - Wave: arm waves and hops with a toy squeak. - Topple: fall onto its back, then get back up. - A finger boop on the face makes it giggle and rock; it also rocks now and then when idle. Palettes: Classic, Yellow, Sorbet. Readouts: mass, volume, steps, rocks. Responsive layout with no horizontal overflow on phones.