ClayGrounds v0.3.4 — Native DAI Entities

- Added 9 registry-backed DAI EntityTypes under data/claygrounds/dai_entities/.
- Enemy spawns now use claygrounds:* entity ids instead of vanilla entity ids.
- Retained the existing CustomModelData item-display bodies (2001-2009) so ClayGrounds visuals do not regress.
- Added explicit empty entity loot tables for all 9 custom types; vanilla carrier drops such as string, bones, arrows, rotten flesh and spider eyes no longer leak into ClayGrounds.
- ClayGrounds totalKillCount progression remains the reward source (40 XP + 40 Gold per normal kill).
- Claycrest Archer now uses a native custom skeleton-backed EntityType with a hidden, non-dropping bow for proper ranged AI.
- Shorewarden is now claygrounds:shorewarden and no longer a minecraft:ravager identity. Its visible model, bossbar, coordinates and progression reward remain unchanged.
- Natural spawning is disabled for every custom entity; ClayGrounds' authored anchor spawn-cycle remains authoritative.

IMPORTANT: registry-backed ids are discovered during DAI early bootstrap. Replace the datapack while Minecraft is CLOSED, then launch fresh. The startup log should report 9 native ids prepared from disk, and datapack reload should report 9 entity definitions loaded from dai_entities.
