Mob Destroy Refactoring (#22573)

Refactoring the entire destroy proc path from Mob Human all the way down
to Atom while trying to find the causes for the damn mob human hard
deletes. This PR comprehensively reorganizes every single stray
snowflake var used by /atom/ all the way to /mob/living/carbon/human,
and makes sure that every var that COULD store a reference, is now
cleared during the entirety of the Mob Destroy() parent hierarchy.

This may very well be the end of the lag war. 

In total, I've hunted down and cleared 39 hanging references between
/atom and /mob/living/carbon/human

---------

Signed-off-by: VMSolidus <evilexecutive@gmail.com>

code/modules/mob/mob.dm

@@ -1,32 +1,90 @@
 /mob/Destroy()//This makes sure that mobs with clients/keys are not just deleted from the game.
 	MOB_STOP_THINKING(src)
-	// Tell any mobs touching us that they're not pulling us anymore.
-	stop_pulling()
 	// Delete and null the grab objects that are touching this mob.
 	QDEL_LIST(grabbed_by)
 	GLOB.mob_list -= src
 	GLOB.dead_mob_list -= src
 	GLOB.living_mob_list -= src
 	GLOB.player_list -= src
-	unset_machine()
 	QDEL_NULL(hud_used)
 
+	QDEL_NULL(cells)
+	QDEL_NULL(flash)
+	QDEL_NULL(blind)
+	QDEL_NULL(hands)
+	QDEL_NULL(pullin)
+	QDEL_NULL(purged)
+	QDEL_NULL(internals)
+	QDEL_NULL(oxygen)
+	QDEL_NULL(paralysis_indicator)
+	QDEL_NULL(i_select)
+	QDEL_NULL(m_select)
+	QDEL_NULL(toxin)
+	QDEL_NULL(bodytemp)
+	QDEL_NULL(healths)
+	QDEL_NULL(throw_icon)
+	QDEL_NULL(nutrition_icon)
+	QDEL_NULL(hydration_icon)
+	QDEL_NULL(pressure)
+	QDEL_NULL(damageoverlay)
+	QDEL_NULL(pain)
+	QDEL_NULL(item_use_icon)
+	QDEL_NULL(radio_use_icon)
+	QDEL_NULL(gun_move_icon)
+	QDEL_NULL(gun_setting_icon)
+	QDEL_NULL(unique_action_icon)
+	QDEL_NULL(toggle_firing_mode)
+	QDEL_NULL(energy_display)
+	QDEL_NULL(instability_display)
+	QDEL_NULL(up_hint)
+	QDEL_NULL(robot_pain)
 	QDEL_LIST(spell_masters)
-	remove_screen_obj_references()
-
 	if(client)
 		for(var/atom/movable/AM in client.screen)
-			qdel(AM)
+			if (!QDELING(AM))
+				qdel(AM)
 		client.screen = list()
 
-	if (mind)
-		mind.handle_mob_deletion(src)
+	mind?.handle_mob_deletion(src)
+	mind = null
 
-	for(var/cc in client_colors)
-		qdel(cc)
+	QDEL_NULL(ability_master)
+	QDEL_NULL(zone_sel)
+	machine = null
 
-	client_colors = null
+	pulling?.pulledby = null
+	pulling = null
+	pullin?.icon_state = "pull0"
+	pullin = null
+
+	QDEL_LIST(client_colors)
+	additional_vision_handlers?.Cut()
+	pinned?.Cut()
+	QDEL_LIST(embedded)
+	languages?.Cut()
+	holo = null
+	l_hand = null
+	r_hand = null
+	back = null
+	internal = null
+	s_active = null
+	wear_mask = null
+	QDEL_NULL(dna)
+	QDEL_NULL(LAssailant)
+	spell_list?.Cut()
+	lastarea = null
+	control_object = null
+	teleop = null
+	listed_turf = null
 	item_verbs = null
+	// This is a nested assoc list, which must be cleared outside-in
+	if (length(progressbars))
+		for (var/location in progressbars)
+			for (var/ref in progressbars[location])
+				qdel(ref)
+		progressbars.Cut()
+
+	QDEL_NULL(typing_indicator)
 
 	//Added this to prevent nonliving mobs from ghostising
 	//The only non 'living' mobs are:
@@ -44,11 +102,21 @@
 		var/atom/movable/AM = src.loc
 		LAZYREMOVE(AM.contained_mobs, src)
 
-	QDEL_NULL(ability_master)
-
-	if(click_handlers)
-		QDEL_LIST(click_handlers)
-
+	QDEL_LIST(click_handlers)
+	vr_mob = null
+	old_mob = null
+	lastattacker = null
+	lastattacked = null
+	QDEL_NULL(pointing_effect)
+	QDEL_LIST(open_nanouis)
+	QDEL_LIST(tgui_open_uis)
+	QDEL_NULL(narsimage)
+	QDEL_NULL(narglow)
+	QDEL_NULL(riftimage)
+	QDEL_NULL(bloody_hands_mob)
+	QDEL_NULL(eyeobj)
+	QDEL_NULL(bg)
+	my_client = null
 	return ..()
 
 /mob/New()
@@ -56,32 +124,6 @@
 	GenerateTag()
 	return ..()
 
-/mob/proc/remove_screen_obj_references()
-	flash = null
-	blind = null
-	hands = null
-	pullin = null
-	purged = null
-	internals = null
-	oxygen = null
-	i_select = null
-	m_select = null
-	toxin = null
-	bodytemp = null
-	healths = null
-	throw_icon = null
-	nutrition_icon = null
-	hydration_icon = null
-	pressure = null
-	damageoverlay = null
-	pain = null
-	item_use_icon = null
-	gun_move_icon = null
-	gun_setting_icon = null
-	spell_masters = null
-	zone_sel = null
-
-/mob/var/should_add_to_mob_list = TRUE
 /mob/Initialize(mapload)
 	. = ..()
 	if(should_add_to_mob_list)
@@ -400,8 +442,6 @@
 	if(!. && iscarbon(loc) && isturf(loc.loc)) // We're inside someone, let us examine still.
 		return TRUE
 
-/mob/var/obj/effect/decal/point/pointing_effect = null//Spam control, can only point when the previous pointer qdels
-
 /mob/verb/pointed(atom/A as mob|obj|turf in view())
 	set name = "Point To"
 	set category = "Object"
@@ -730,8 +770,8 @@
 	if(pulling)
 		pulling.pulledby = null
 		pulling = null
-		if(pullin)
-			pullin.icon_state = "pull0"
+	if(pullin)
+		pullin.icon_state = "pull0"
 
 /mob/proc/start_pulling(var/atom/movable/AM)