Flashing ancient debries

Makes Ancient Debris blink (flashes gold every ~0.4s) instead of blending into the Nether stone. Only overwrites 2 textures, no shader needed — stacks fine with other packs.

Uses: much easier to spot while strip-mining/netherite farming, and works great combined with a Clear Lava pack — you'd see it flashing right through the lava around it, like an X-ray effect but legit.