Create an original Gundam-inspired sci-fi mecha, teal-black or starfield tone, PBR textures, glTF 2.0 (.glb). Must have separate meshes named head, torso, left_arm, right_arm, left_leg, right_leg (plus optional hands, backpack, weapon). Each mesh must be independent geometry with pivot at its joint center for animation. Triangle count 10k–30k, UV unwrapped, 2048 textures. Provide transparent PNG preview and JSON metadata with mesh centers and explosion direction vectors.