Fixes harddels in pinned module code, cleans up a musty pattern that I want to die (#64674)

* Please stop typecasting target, noooooooooooooooooo

* Fixes harddels in pinned module code

The logic for pinned modules was intentionally hanging references to the
mob that pinned the action button. I have depression.

The pinned_to list also was never fully cleared, but that would have
just exasperated the issue. I've converted its use of mobs to refs, and
its use of the module var into something better managed

(Friendly reminder that actions will persist in your nightmares forever
unless they are manually qdel'd, this code wasn't doing that.

Also cleaned up how the pinned_to list is managed, hopefully it's a bit
more action centered now

code/modules/mod/mod_actions.dm

@@ -4,16 +4,17 @@
 	check_flags = AB_CHECK_CONSCIOUS
 	/// Whether this action is intended for the AI. Stuff breaks a lot if this is done differently.
 	var/ai_action = FALSE
-	/// The MODsuit linked to this action
-	var/obj/item/mod/control/mod
 
 /datum/action/item_action/mod/New(Target)
 	..()
-	mod = Target
+	if(!istype(Target, /obj/item/mod/control))
+		qdel(src)
+		return
 	if(ai_action)
 		background_icon_state = ACTION_BUTTON_DEFAULT_BACKGROUND
 
 /datum/action/item_action/mod/Grant(mob/user)
+	var/obj/item/mod/control/mod = target
 	if(ai_action && user != mod.ai)
 		return
 	else if(!ai_action && user == mod.ai)
@@ -21,6 +22,7 @@
 	return ..()
 
 /datum/action/item_action/mod/Remove(mob/user)
+	var/obj/item/mod/control/mod = target
 	if(ai_action && user != mod.ai)
 		return
 	else if(!ai_action && user == mod.ai)
@@ -30,6 +32,7 @@
 /datum/action/item_action/mod/Trigger(trigger_flags)
 	if(!IsAvailable())
 		return FALSE
+	var/obj/item/mod/control/mod = target
 	if(mod.malfunctioning && prob(75))
 		mod.balloon_alert(usr, "button malfunctions!")
 		return FALSE
@@ -44,6 +47,7 @@
 	. = ..()
 	if(!.)
 		return
+	var/obj/item/mod/control/mod = target
 	if(trigger_flags & TRIGGER_SECONDARY_ACTION)
 		mod.quick_deploy(usr)
 	else
@@ -71,6 +75,7 @@
 		UpdateButtonIcon()
 		addtimer(CALLBACK(src, .proc/reset_ready), 3 SECONDS)
 		return
+	var/obj/item/mod/control/mod = target
 	reset_ready()
 	mod.toggle_activate(usr)
 
@@ -94,6 +99,7 @@
 	. = ..()
 	if(!.)
 		return
+	var/obj/item/mod/control/mod = target
 	mod.quick_module(usr)
 
 /datum/action/item_action/mod/module/ai
@@ -108,6 +114,7 @@
 	. = ..()
 	if(!.)
 		return
+	var/obj/item/mod/control/mod = target
 	mod.ui_interact(usr)
 
 /datum/action/item_action/mod/panel/ai
@@ -119,8 +126,8 @@
 	var/override = FALSE
 	/// Module we are linked to.
 	var/obj/item/mod/module/module
-	/// Mob we are pinned to.
-	var/mob/pinner
+	/// A ref to the mob we are pinned to.
+	var/pinner_ref
 
 /datum/action/item_action/mod/pinned_module/New(Target, obj/item/mod/module/linked_module, mob/user)
 	if(isAI(user))
@@ -131,13 +138,21 @@
 	desc = "Quickly activate [linked_module]."
 	icon_icon = linked_module.icon
 	button_icon_state = linked_module.icon_state
-	pinner = user
 	RegisterSignal(linked_module, COMSIG_MODULE_ACTIVATED, .proc/on_module_activate)
 	RegisterSignal(linked_module, COMSIG_MODULE_DEACTIVATED, .proc/on_module_deactivate)
 	RegisterSignal(linked_module, COMSIG_MODULE_USED, .proc/on_module_use)
 
+/datum/action/item_action/mod/pinned_module/Destroy()
+	module.pinned_to -= pinner_ref
+	module = null
+	return ..()
+
 /datum/action/item_action/mod/pinned_module/Grant(mob/user)
-	if(user != pinner)
+	var/user_ref = REF(user)
+	if(!pinner_ref)
+		pinner_ref = user_ref
+		module.pinned_to[pinner_ref] = src
+	else if(pinner_ref != user_ref)
 		return
 	return ..()
 
@@ -145,6 +160,7 @@
 	. = ..()
 	if(!.)
 		return
+	var/obj/item/mod/control/mod = target
 	if(!mod.active)
 		mod.balloon_alert(usr, "suit not on!")
 	module.on_select()
@@ -153,6 +169,7 @@
 	. = ..(current_button, force = TRUE)
 	if(override)
 		return
+	var/obj/item/mod/control/mod = target
 	if(module == mod.selected_module)
 		current_button.add_overlay(image(icon = 'icons/hud/radial.dmi', icon_state = "module_selected", layer = FLOAT_LAYER-0.1))
 	else if(module.active)