Adds the bloodroach (#91383)

## About The Pull Request

Adds bloodroaches.


![image](https://github.com/user-attachments/assets/2f122787-0a22-4ff3-9c9b-7e14ca479369)

These are cockroaches that have gorged themselves on blood in
maintenance. They're very gross!


![image](https://github.com/user-attachments/assets/1ff744ed-a61b-4f6b-8d1c-28664f7a953f)

Splatting one causes an explosion of blood all around the death
perimeter, splashing both turfs and mobs with blood.

They have a 1% chance of spawning in place of normal roaches.

They also spawn in:
- Abandoned crates, replacing the 30 roaches with 30 bloodroaches.
- As backup anomalous crystal possession targets.
- Grimy fridges

Added a trait given to things killed by pest spray, used to check on
death explosion for bloodroaches.
Changed roach spawns in maps to use mob spawners, so I can replace them
with bloodroaches 1% of the time.
## Why It's Good For The Game

Splatting a random roach in maintenance that explodes into blood sounds
hilarious. It also adds janitorial depth by requiring pest spray to
carefully eliminate these pests
## Changelog
🆑
add: Added bloodroaches, a rare variant of cockroaches that explode into
a shower of blood when squashed.
/🆑

code/modules/mob_spawn/mob_spawn.dm

@@ -364,3 +364,14 @@
 //don't use this in subtypes, just add 1000 brute yourself. that being said, this is a type that has 1000 brute. it doesn't really have a home anywhere else, it just needs to exist
 /obj/effect/mob_spawn/corpse/human/damaged
 	brute_damage = 1000
+
+/obj/effect/mob_spawn/cockroach
+	name = "Cockroach Spawner"
+	desc = "A spawner for cockroaches, the most common vermin in the station. Small chance to spawn a bloodroach."
+	mob_type = /mob/living/basic/cockroach
+	var/bloodroach_chance = 1 // 1% chance to spawn a bloodroach
+
+/obj/effect/mob_spawn/cockroach/Initialize(mapload)
+	if(prob(bloodroach_chance))
+		mob_type = /mob/living/basic/cockroach/bloodroach
+	return ..()