fix: single-click confirms item selection instead of requiring two clicks

inventory/inventory_overlay/InventoryOverlay.gd

@@ -106,7 +106,8 @@ func _on_slot_clicked(item_id: String) -> void:
 				_is_dragging = true
 				_create_drag_preview(child)
 			elif _selected_slot.item_id == item_id:
-				_handle_release_same_item()
+				item_confirmed.emit(item_id)
+				hide_overlay()
 			else:
 				combine_requested.emit(_selected_slot.item_id, item_id)
 				_clear_selection()