EnhancedAnvil

### Added

- Added the disenchantment system for dropped enchanted tools, weapons, armor,
  and enchanted books.
- Added Obsidian and Crying Obsidian base-block validation.
- Added falling-anvil activation for both vanilla anvils and the Enhanced Anvil.
- Added plain Book extraction costs:
  - One plain Book per removed enchantment.
  - Two plain Books to split a multi-enchantment book.
- Added curse-first enchantment extraction.
- Added partial extraction when fewer plain Books are available.
- Added batch processing for item stacks.
- Added multi-enchantment book splitting into separate enchanted books.
- Added prior-work/repair-cost clearing on returned items.
- Added outward movement to generated output drops to reduce item overlap.

### Fixed

- Fixed disenchantment activation so it is not limited to the Enhanced Anvil
  block's land callback.
- Fixed falling-anvil detection on Obsidian and Crying Obsidian.
- Removed the full-world entity scan that ran every server tick and caused
  gameplay lag.
- Falling anvils are now tracked only while they exist, using Forge entity join
  and leave events.
- Normal gameplay no longer performs a recurring world-wide entity search.