ClayGrounds v0.3.1 — NATIVE OCEAN WORLD

- Replaces runtime ocean construction with a real Minecraft datapack world preset: claygrounds:claygrounds_ocean.
- The Overworld generator is flat and begins with the exact ClayGrounds ocean geometry already present:
  - Y -64..54: air
  - Y 55: sand seabed
  - Y 56..61: water
  - Y 62+: air
- The dry Solmere arrival platform begins at Y62, exactly above sea level.
- No broad ocean /fill phase exists at startup or completion.
- Removed the 64 manual ocean cells from v0.3.0.
- Removed unused broad-ocean build steps 344..373.
- Island/structure build is 344 terrain steps at approximately 2x TamaCrafti cadence.
- Only five tiny authored local-water operations remain for the fountain and Verdant feature.
- Loading HUD is terrain-only: 0/344 -> 344/344, with a ~28 second initial estimate.
- Existing island geometry, class altars, enemy anchors, Grotto gate, Shorewarden, fountain, labels, combat logic, and model IDs are preserved.

DAI NOTE
DAI 1.9.1 exposes `world_preset`, not Minecraft's separate `flat_level_generator_preset` selector. This patch therefore uses the supported normal datapack world-preset path rather than pretending `minecraft:water_world` is a world-preset id.
