refactors radios to use proximity (#25303)

* refactors radios to use proximity

* Apply suggestions from code review

Signed-off-by: DGamerL <108773801+DGamerL@users.noreply.github.com>

---------

Signed-off-by: DGamerL <108773801+DGamerL@users.noreply.github.com>
Co-authored-by: DGamerL <108773801+DGamerL@users.noreply.github.com>

code/modules/mob/dead/observer/observer_base.dm

@@ -825,5 +825,11 @@ This is the proc mobs get to turn into a ghost. Forked from ghostize due to comp
 /mob/dead/observer/get_runechat_color()
 	return alive_runechat_color
 
+/mob/dead/observer/proc/update_dead_radio()
+	if(get_preference(PREFTOGGLE_CHAT_GHOSTRADIO))
+		GLOB.deadchat_radio.listeners |= src
+	else
+		GLOB.deadchat_radio.listeners -= src
+
 #undef GHOST_CAN_REENTER
 #undef GHOST_IS_OBSERVER

code/modules/mob/dead/observer/observer_login.dm

@@ -10,3 +10,5 @@
 	if(GLOB.non_respawnable_keys[ckey])
 		can_reenter_corpse = 0
 		REMOVE_TRAIT(src, TRAIT_RESPAWNABLE, GHOSTED)
+	
+	update_dead_radio()