Introduce LootService for chest loot handling and ChestListener for in-game chest interactions

src/main/java/com/alttd/hunger_games/services/LootService.java

@@ -0,0 +1,62 @@
+package com.alttd.hunger_games.services;
+
+import com.alttd.hunger_games.config.LootItems;
+import com.alttd.hunger_games.data_objects.RARITY;
+import net.kyori.adventure.text.Component;
+import org.bukkit.Bukkit;
+import org.bukkit.Location;
+import org.bukkit.Material;
+import org.bukkit.inventory.Inventory;
+import org.bukkit.inventory.ItemStack;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Random;
+import java.util.concurrent.ThreadLocalRandom;
+
+public class LootService {
+
+    private final HashMap<Location, Inventory> chestInventories = new HashMap<>();
+    private final Random random = ThreadLocalRandom.current();
+
+    public Inventory getChestInventory(Location location) {
+        if (chestInventories.containsKey(location)) {
+            return chestInventories.get(location);
+        }
+
+        Inventory inventory = generateLoot();
+        chestInventories.put(location, inventory);
+        return inventory;
+    }
+
+    private Inventory generateLoot() {
+        Inventory inventory = Bukkit.createInventory(null, 27, Component.text("Chest"));
+        RARITY rarity = decideRarity();
+        List<Material> possibleItems = LootItems.ITEMS.get(rarity);
+
+        if (possibleItems.isEmpty()) {
+            return inventory;
+        }
+
+        int itemCount = random.nextInt(3, 7);
+        for (int i = 0; i < itemCount; i++) {
+            int slot = random.nextInt(27);
+            Material material = possibleItems.get(random.nextInt(possibleItems.size()));
+            inventory.setItem(slot, new ItemStack(material));
+        }
+
+        return inventory;
+    }
+
+    private RARITY decideRarity() {
+        double roll = random.nextDouble();
+        if (roll < 0.05) return RARITY.EPIC;    // 5%
+        if (roll < 0.15) return RARITY.RARE;    // 10%
+        if (roll < 0.40) return RARITY.UNCOMMON;// 25%
+        return RARITY.COMMON;                   // 60%
+    }
+
+    public void clear() {
+        chestInventories.clear();
+    }
+}