i think it works

MAJOR antag backend update
- you cannot bruteforce the pen anymore
- uplink now uses bitflag to lock purchases
- poplock is handled entirely by the buyable uplink items
- tgui antag intro (for selected ones)

code/modules/modular_computers/computers/item/computer_ui.dm

@@ -118,12 +118,6 @@
 			update_appearance()
 			if(user && istype(user))
 				ui_interact(user) // Re-open the UI on this computer. It should show the main screen now.
-		if("eject_pen")
-			if(istype(src, /obj/item/modular_computer/tablet))
-				var/obj/item/modular_computer/tablet/self = src
-				if(self.can_have_pen)
-					self.remove_pen()
-				return
 
 		if("PC_killprogram")
 			var/prog = params["name"]