Hopper Filter and Upgrade Notes

• Implemented a Paper plugin that gives each hopper a configurable item filter and an upgradeable transfer amount.
• Sneak + right-click a hopper to open the filter menu: place sample items to allow them, clear slots to remove entries. Your items are returned when the menu closes; placeholder samples inside the menu are removed automatically.
• Sneak + right-click a hopper while holding a Hopper Upgrade Kit to increase its transfer batch size by 1 per level (max level 5). The kit is consumed on successful upgrade.
• Hoppers respect the saved filter list for both pulling and pushing items; anything not on the list is blocked. Upgrades let a hopper move multiple items per transfer instead of the default single item, capped by the source stack size and a max level of 5.
• Use the /hopperupgrade command to obtain a Hopper Upgrade Kit. Grant this to trusted players as needed.
• Notes/Suggestions: filters match only by material type (not enchantments or NBT). Consider adding a crafting recipe or permission checks for the kit command if you want tighter control.

Server Validation

✅ Server validation passed - The mod was tested on a real Minecraft server and loaded successfully.