Port over remaining Lavaland ruins

code/modules/nano/nanoexternal.dm

@@ -40,6 +40,14 @@
 /datum/proc/ui_interact(mob/user, ui_key = "main", var/datum/nanoui/ui = null, var/force_open = 1, var/datum/nano_ui/master_ui = null, var/datum/topic_state/state = default_state)
 	return
 
+/**
+  * The UI-close proc is called when the UI is closed.
+  *
+  * @param user /mob The mob who was interacting with this UI.
+  */
+/datum/proc/on_ui_close(mob/user)
+	return
+
 /**
  * The ui_data proc is used to get data for the interface
  *

code/modules/nano/nanoui.dm

@@ -444,6 +444,8 @@ nanoui is used to open and update nano browser uis
 	for(var/datum/nanoui/child in children)
 		child.close()
 
+	src_object.on_ui_close(user)
+
  /**
   * Set the UI window to call the nanoclose verb when the window is closed
   * This allows Nano to handle closed windows