Neroland Core

Additive public-API release for off-Earth content: a shared "where is space?" tag vocabulary and a cross-loader entity registration seam. Every existing API signature, tag, id, capability and config key is unchanged.

Added

Space tags (za.co.neroland.nerolandcore.worldgen.SpaceTags)

• The neroland:space/* vocabulary — biome tags space/dark_biomes, space/moon_biomes, space/crystalline_biomes, space/asteroid_biomes and the umbrella space/planet_biomes, plus the dimension-type tag space/dimensions. Core owns the ids; the mods that own the planets supply the members.
• Base membership shipped in data/neroland/tags/worldgen/biome/space/ and data/neroland/tags/dimension_type/space/, with every entry "required": false — Nerospace's biomes themed from their own JSON plus nerospace:gravity_* membership, and best-effort Ad Astra entries on the usual tag-mediated, no-hard-dependency footing. space/planet_biomes includes the four themed tags by reference.
• Helpers isSpace(ServerLevel), biomeIn(Holder<Biome>, TagKey<Biome>) and biomeIn(LevelReader, BlockPos, TagKey<Biome>). Empty tags are a supported state — consumers must read an empty tag as "no such place here", never as an error.

Entity registration seam (za.co.neroland.nerolandcore.entity.EntityRegistrationSupport)

• Declare a mob's default attributes and natural spawn placement once from common code: get(modId).registerAttributes(typeSupplier, builderSupplier) and registerSpawnPlacement(typeSupplier, placementType, heightmap, predicate). Both take suppliers so a RegistrationProvider.RegistryEntry can be passed straight in on the deferred-register loaders.
• Buffered in common and flushed by per-loader plumbing (a ServiceLoader seam, EntityRegistrationSupport$Plumbing): NeoForge EntityAttributeCreationEvent / RegisterSpawnPlacementsEvent, Forge EntityAttributeCreationEvent / SpawnPlacementRegisterEvent, Fabric FabricDefaultAttributeRegistry plus the vanilla SpawnPlacements.register applied immediately.
• Requires no loader wiring downstream — Core installs the flush listeners during its own bootstrap and the events reach every mod. attach(loaderEventBus) is offered for parity with RegistrationProvider.attach(...) and is idempotent; every buffered entry is applied at most once, and a failing entry is logged (mod id only) rather than aborting the batch.
• New docs page docs/SPACE-TAGS-AND-ENTITIES.md and wiki page wiki/Space-Tags-and-Entities.md.