Undertone

First release: the helpers my NeoForge mods share, bundled into each with jar-in-jar.

• Registrar: one per mod, under the mod's own namespace. It hands out NeoForge's registers for every registry and adds them to the mod's bus in one call, refusing a bus that isn't the mod's.
• Creative tab groups: ItemRegister.group and BlockRegister.group put every item in a group's tabs, and creativeTab adds more per item, each tab holding an item once.
• Shorthands for data components (flag, persistent), block entity types, and menu types that open with data (DataMenuType).
• Codecs.enumMap, which reads into an EnumMap.
• SyncedBlockEntity, which sends clients what it saves.
• PlayerInventorySlots and SlotRange for menus.
• ModelWrapper and BlockModels.wrap for models drawn in code.