Better Stacking

## Fixed

- **Enchanting tables now work with stacked items.** Minecraft refuses to
  enchant anything with a max stack size above 1, so making tools and armor
  stackable silently made them un-enchantable. Books were the only exception
  because they use a different internal check. Tools, armor, bows and fishing
  rods can be enchanted normally again.
- **No more lost buckets.** Emptying a bucket makes Minecraft replace your
  entire held stack with one empty bucket — it was never written for stacked
  buckets, because vanilla buckets can't stack. Filled buckets, milk, stews,
  soups and book-and-quill are now left unstackable to prevent this.
- **Shulker boxes are no longer stackable.** Placing one from a stack could
  duplicate its contents.

## Added

- **Config file** (`config/betterstacking-common.toml`):
  - Set your own stack size, anywhere from 2 to 99
  - Toggle tools/armor, 1-stack items and 16-stack items separately
  - Blacklist specific items or whole mods (`modid:*`)
  - Whitelist-only mode to raise just the items you pick
- **Plays nicely with other stack mods.** Better Stacking only touches items
  still at Minecraft's default of 1 or 16, and never lowers a value another
  mod already set.

## Known issues

- Repairing a **stack** of tools in an anvil or grindstone consumes the whole
  stack for one result. Set `affectDamageableItems = false` if you repair in
  bulk. A proper fix is coming.
- Damaged tools and armor won't merge into a stack. This is vanilla behavior
  and changing it would break how durability is stored.