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/modules/reagents/Chemistry-Reagents/Chemistry-Reagents-Drugs.dm

@@ -312,7 +312,7 @@
 	M.hallucination = max(M.hallucination, drug_strength)
 
 	if(prob(15))
-		to_chat(SPAN_GOOD(pick("The floor is melting...", "Everything is so much brighter! Wow!", "Everything is shifting around you.")))
+		to_chat(M, SPAN_GOOD(pick("The floor is melting...", "Everything is so much brighter! Wow!", "Everything is shifting around you.")))
 
 
 /singleton/reagent/drugs/night_juice