RLCraft Improved Backpacks

[1.0.14] - 2026-05-29
- Added gem color slot: fuse a backpack with a supported gem on an anvil to change
  the backpack's tint color. The tint applies to both the inventory icon and the 3D
  model worn on the player's back (uses WearableBackpacks' existing IItemColor hook).
  The gem slot is NBT-only and does not affect bauble slots.
  Supported gems:
    Ruby (biomesoplenty:gem meta=1)        → deep red    (#AB2323)
    Scarlite (defiledlands:scarlite)       → scarlet     (#CC3C1C)
    Topaz (biomesoplenty:gem meta=3)       → orange      (#E88020)
    Amber (biomesoplenty:gem meta=7)       → amber       (#E8A030)
    Peridot (biomesoplenty:gem meta=2)     → olive green (#4A8A18)
    Malachite (biomesoplenty:gem meta=5)   → teal green  (#1A8A60)
    Sapphire (iceandfire:sapphire_gem)     → sapphire    (#1040B8)
    Lapis (minecraft:dye meta=4)           → lapis blue  (#1E3EA0)
    Amethyst (iceandfire:amethyst_gem)     → purple      (#8B28C0)
    Tanzanite (biomesoplenty:gem meta=4)   → indigo      (#3A2880)
    Emerald (minecraft:emerald)            → emerald     (#20C840)
  Anvil cost: 4 XP levels; consumes 1 gem.
  Applying a different gem overwrites the previous color.
  Gem color removal: anvil + Water Bucket, cost 2 XP levels.
  Tooltip on a tinted backpack shows "Gem Color: <name>" and the removal hint.