Just Backpacks [DISCONTINUED]

This update introduces the Upgrade Kit System, replacing the per-tier crafting recipes with a progression-based upgrade mechanic that preserves your backpack's contents across every tier transition.

• Upgrade Kits: Five new items — Copper, Iron, Gold, Diamond, and Netherite Upgrade Kits — allow upgrading a backpack to the next tier without losing its contents.
• Usage: Place the backpack in your offhand, hold the Upgrade Kit in your main hand, and interact (Right-click / Long-press).
• Tier-locked: Each kit only works on its matching tier. You cannot skip tiers.
• Recipes: Kits are crafted at the Crafting Table. The Copper Kit requires 4× Copper Ingots; other kit recipes follow the same material pattern.

• Item Lore: Backpacks now show their unique ID, owner name, and current tier directly in the item tooltip.
• New Languages: Added Italian (it_IT), Korean (ko_KR), Polish (pl_PL), and Turkish (tr_TR). The addon now supports 13 languages total.

• Simplified Crafting: Removed individual crafting recipes for tiers 2–6. The Leather Backpack remains the only directly craftable tier.