Water World - Atolls

1.0.3

• Replaced the placeholder Atoll Seed inventory sprite with a 16×16 Water World atoll: wooden boardwalk ring, turquoise lagoon, hut and palms.
• Redrew the Atoll Seed block top and side as the same lagoon-and-pier cube.
• Added the Minecraft 26.2 items/atoll_seed.json definition so the item actually uses that texture.
• Converted the mod icon and banner from JPEG-named files to real PNG.