Change spiderwebs to drain stamina when mobs enter (#95197)

## About The Pull Request
This changes spiderwebs to drain stamina from mobs whenever they enter a
turf filled with spiderwebs.

## Why It's Good For The Game
The old movement code was very janky and buggy. Because it used the
`CanAllowThrough` proc, a mob could spam several dozens of movement
attempts per second, resulting in a massive amount of shaking and `stuck
in the web` messages. This had the effect of not really slowing or
stopping movement, since the RNG was being rolled so fast that it was a
minor inconvenience.

I feel like the stamina drain effect makes more sense and feels more
natural.

## Changelog
🆑
balance: Sticky spider webs now drain stamina when mobs enter the turf
/🆑

code/game/objects/effects/spiderwebs.dm

@@ -57,6 +57,11 @@
 	if (has_frill)
 		pixel_x = -9
 		pixel_y = -9
+
+	var/static/list/loc_connections = list(
+		COMSIG_ATOM_ENTERED = PROC_REF(on_entered),
+	)
+	AddElement(/datum/element/connect_loc, loc_connections)
 	return ..()
 
 /obj/structure/spider/stickyweb/attack_hand(mob/user, list/modifiers)
@@ -79,23 +84,37 @@
 		return
 	if(sealed)
 		return FALSE
-	if(isliving(mover))
-		if(HAS_TRAIT(mover, TRAIT_WEB_SURFER))
-			return TRUE
-		if(mover.pulledby && HAS_TRAIT(mover.pulledby, TRAIT_WEB_SURFER))
-			return TRUE
-		if(prob(stuck_chance))
-			stuck_react(mover)
-			return FALSE
-		return .
 	if(isprojectile(mover))
 		return prob(projectile_stuck_chance)
 	return .
 
-/// Show some feedback when you can't pass through something
-/obj/structure/spider/stickyweb/proc/stuck_react(atom/movable/stuck_guy)
-	loc.balloon_alert(stuck_guy, "stuck in web!")
-	stuck_guy.Shake(duration = 0.1 SECONDS)
+/obj/structure/spider/stickyweb/proc/on_entered(datum/source, atom/movable/victim, old_loc)
+	SIGNAL_HANDLER
+
+	if(!isliving(victim))
+		return
+	if(HAS_TRAIT(victim, TRAIT_WEB_SURFER))
+		return
+	if(victim.pulledby && HAS_TRAIT(victim.pulledby, TRAIT_WEB_SURFER))
+		return
+
+	if(prob(stuck_chance))
+		stuck_react(victim)
+
+/// Drains stamina and shows feedback when you get stuck moving thru a web
+/obj/structure/spider/stickyweb/proc/stuck_react(mob/living/victim)
+	if(victim.get_stamina_loss() > 90)
+		if(victim.body_position != LYING_DOWN)
+			to_chat(victim, span_warning("You trip over \the [src] due to exhaustion!"))
+
+		victim.SetKnockdown(3 SECONDS)
+		return
+
+	if(prob(25))
+		loc.balloon_alert(victim, "stuck in web!")
+		victim.Shake(duration = 0.2 SECONDS)
+
+	victim.adjust_stamina_loss(rand(10, 15))
 
 /// Web made by geneticists, needs special handling to allow them to pass through their own webs
 /obj/structure/spider/stickyweb/genetic