EnhancedAnvil

### Added

- Added the disenchantment system using a falling anvil.
- Enchanted tools, weapons, and armor can be processed when an anvil lands above obsidian or crying obsidian.
- Each removed enchantment produces a separate enchanted book.
- Curse enchantments are removed first, followed by the remaining enchantments in a stable order.
- Plain books are consumed at a rate of one book per removed enchantment.
- Multi-enchantment books can be split into single-enchantment books and require two plain books.
- Single-enchantment books are left unchanged.
- Added batch processing for item stacks, subject to the available plain books and server limits.
- Cleared prior-work/repair cost from stripped items.
- Added outward nudging and small movement to generated item drops to reduce item overlap.
- Added support for both normal obsidian and crying obsidian.

### Fixed

- Fixed the falling-anvil disenchantment trigger by processing active falling anvils directly during server ticks.
- Added a delayed landing check so the anvil and nearby item entities are available before disenchantment starts.
- Removed fragile dependence on falling-entity join/leave timing.
- Expanded the item search area around the landing position.
- Fixed Enhanced Anvil results showing `Too Expensive` after several enchantments.
- Enhanced Anvil operations now display a usable XP cost capped below vanilla's 40-level `Too Expensive` threshold.
- XP cost now grows from the complete resulting enchantment set, so adding more enchantments increases the displayed cost progressively.
- Removed accumulated prior-work cost from Enhanced Anvil enchantment operations.
- Enhanced Anvil outputs now clear the prior-work/repair cost instead of carrying it forward.