Added CaptiveItemChangeEvent

eco-api/src/main/java/com/willfp/eco/core/gui/menu/events/CaptiveItemChangeEvent.java

@@ -0,0 +1,22 @@
+package com.willfp.eco.core.gui.menu.events;
+
+import com.willfp.eco.core.gui.menu.MenuEvent;
+import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * Represents a captive item change.
+ *
+ * @param row    The row.
+ * @param column The column.
+ * @param before The previous item in the slot.
+ * @param after  The new item in the slot.
+ */
+public record CaptiveItemChangeEvent(
+        int row,
+        int column,
+        @Nullable ItemStack before,
+        @Nullable ItemStack after
+) implements MenuEvent {
+
+}

eco-core/core-backend/src/main/kotlin/com/willfp/eco/internal/gui/menu/RenderedInventory.kt

@@ -1,5 +1,6 @@
 package com.willfp.eco.internal.gui.menu
 
+import com.willfp.eco.core.gui.menu.events.CaptiveItemChangeEvent
 import com.willfp.eco.core.items.isEmpty
 import com.willfp.eco.core.recipe.parts.EmptyTestableItem
 import com.willfp.eco.util.MenuUtils
@@ -63,6 +64,20 @@ class RenderedInventory(
         captiveItems.clear()
         captiveItems.putAll(newCaptive)
 
+        // Call captive item change event
+        for (position in previousCaptive.keys union newCaptive.keys) {
+            if (previousCaptive[position] != newCaptive[position]) {
+                menu.callEvent(
+                    player, CaptiveItemChangeEvent(
+                        position.row,
+                        position.column,
+                        previousCaptive[position],
+                        newCaptive[position]
+                    )
+                )
+            }
+        }
+
         menu.runOnRender(player)
 
         // Run second render if captive items changed