Create a Minecraft Paper/Spigot plugin using Java. Main requirements: It must run Smoothly Core System: * Add 4 custom items called: * Fire Core * Ice Core * Blood Core * Poison Core * Each core should be a custom item with a display name (no color codes needed) * Each core must have a crafting recipe using a 3x3 grid: * Outer slots use a material related to the core (blaze powder, snowball, redstone, spider eye) * Center is a nether star Ability System: * Abilities activate when: * Player is sneaking * Player left clicks * Player is holding a core * Ability only