Begin, the Lag Wars Have (#21839)

<img width="700" height="848" alt="image"
src="https://github.com/user-attachments/assets/e0db50af-35db-43c7-b78e-6c1ea5ac569c"
/>

you take a tiny little two year LOA and this happens
this PR hits some large lag culprits:
- UpdateOverlays() getting spammed by human/update_icon. This was 0.85%
of server CPU time during the event. Doesn't sound like a whole lot but
it's insane. 99% of it was caused by sloppy duplicate calls of
update_icon in set_dir (as well as update icon itself!). Refactored to
stop that
- Makes Follow menu update manually, which cuts down on the 2.8 million
REF() calls it made during the event. This was ~1% of CPU time including
ui_data as well.
- Gets rid of a bunch of random runtimes and some lighting-related
harddels.
- NanoUIs now clean themselves up when their owner qdels rather than
forcing the owner to do REF(src) and close all matching UIs. saves us
~0.1% server cpu time! wowza!

code/game/objects/items.dm

@@ -257,10 +257,7 @@
 /obj/item/Destroy()
 	if(ismob(loc))
 		var/mob/m = loc
-		m.drop_from_inventory(src)
-		m.update_inv_r_hand()
-		m.update_inv_l_hand()
-		src.loc = null
+		m.drop_from_inventory(src, null)
 
 	if(!QDELETED(action))
 		QDEL_NULL(action) // /mob/living/proc/handle_actions() creates it, for ungodly reasons
@@ -930,7 +927,7 @@ GLOBAL_LIST_INIT(slot_flags_enumeration, list(
 	user.langchat_speech("holds up [src].", viewers, GLOB.all_languages, skip_language_check = TRUE, animation_style = LANGCHAT_FAST_POP, additional_styles = list("langchat_small", "emote"))
 	for (var/mob/M in viewers)
 		if(!user.is_invisible_to(M))
-			M.show_message("<b>[user]</b> holds up [icon2html(src, viewers)] [src]. <a href='byond://?src=[REF(M)];lookitem=[REF(src)]'>Take a closer look.</a>",1)
+			M.show_message("<b>[user]</b> holds up [icon2html(src, M)] [src]. <a href='byond://?src=[REF(M)];lookitem=[REF(src)]'>Take a closer look.</a>",1)
 
 /mob/living/carbon/verb/showoff()
 	set name = "Show Held Item"