Add AutoSell feature with commands and tasks for automated item selling

src/main/java/com/alttd/events/ItemPickupEvent.java

@@ -0,0 +1,32 @@
+package com.alttd.events;
+
+import com.alttd.util.auto_sell.AutoSellTask;
+import org.bukkit.entity.Player;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.EventPriority;
+import org.bukkit.event.Listener;
+import org.bukkit.event.entity.EntityPickupItemEvent;
+
+import java.util.UUID;
+
+public class ItemPickupEvent implements Listener {
+
+    private final AutoSellTask autoSellTask;
+
+    public ItemPickupEvent(AutoSellTask autoSellTask) {
+        this.autoSellTask = autoSellTask;
+    }
+
+    @EventHandler(priority = EventPriority.MONITOR)
+    public void onItemPickupEvent(EntityPickupItemEvent event) {
+        if (!(event.getEntity() instanceof Player player)) {
+            return;
+        }
+        UUID uuid = player.getUniqueId();
+        if (!autoSellTask.autoSellEnabled(uuid, event.getItem().getItemStack().getType())) {
+            return;
+        }
+        autoSellTask.putAutoSellPlayer(uuid);
+    }
+
+}