Fixes of gib animation, gib remains, adds new (#6668)

# About the pull request

Fixed runner and larva having no gib animation.

Fixed gib remains being broken and invisible, added larva gib remains
from old cm repo.

Added gib animation for boiler from TGMC
tgstation/TerraGov-Marine-Corps#11908.


# Testing Photographs and Procedure
<details>
<summary>Screenshots & Videos</summary>



https://github.com/cmss13-devs/cmss13/assets/100090741/5b9d370d-f7ff-4c2e-8e98-c2c45fffc753

Previously there was no gib remains (basically last frame of gib
animation, that is a cleanable decal), runner and larva just vanished
into thin air while getting gibbed, and boiler had no unique animation,
using old queen animation.

This is how gibbing larva or runner without changes in this pr looks
like


![dreamseeker_GXEmgTxbW9](https://github.com/user-attachments/assets/352878f5-babc-4d5e-9745-97c28ad1ebee)



</details>


# Changelog
:cl:
fix: fixed runner having no gib animation
fix: fixed gib remains being invisible
imageadd: boiler gib animation
imageadd: larva gib remains
/:cl:

---------

Co-authored-by: Drathek <[email protected]>

code/modules/mob/living/carbon/xenomorph/death.dm

@@ -137,25 +137,31 @@
 
 /mob/living/carbon/xenomorph/gib(datum/cause_data/cause = create_cause_data("gibbing", src))
 	var/obj/effect/decal/remains/xeno/remains = new(get_turf(src))
-	remains.icon = icon
+	var/icon_path
+	var/gib_state = "gibbed-a-corpse"
 	remains.pixel_x = pixel_x //For 2x2.
 
 	if(!caste)
 		CRASH("CASTE ERROR: gib() was called without a caste. (name: [name], disposed: [QDELETED(src)], health: [health])")
 
-	switch(caste.caste_type) //This will need to be changed later, when we have proper xeno pathing. Might do it on caste or something.
+	if(mob_size >= MOB_SIZE_BIG)
+		icon_path = 'icons/mob/xenos/xenomorph_64x64.dmi'
+	else
+		icon_path = 'icons/mob/xenos/xenomorph_48x48.dmi'
+	switch(caste.caste_type)
+		if(XENO_CASTE_RUNNER)
+			icon_path = 'icons/mob/xenos/xenomorph_64x64.dmi'
+			gib_state = "gibbed-a-corpse-runner"
 		if(XENO_CASTE_BOILER)
 			var/mob/living/carbon/xenomorph/boiler/src_boiler = src
 			visible_message(SPAN_DANGER("[src] begins to bulge grotesquely, and explodes in a cloud of corrosive gas!"))
 			src_boiler.smoke.set_up(2, 0, get_turf(src), new_cause_data = src_boiler.smoke.cause_data)
 			src_boiler.smoke.start()
-			remains.icon_state = "gibbed-a-corpse"
-		if(XENO_CASTE_RUNNER)
-			remains.icon_state = "gibbed-a-corpse-runner"
 		if(XENO_CASTE_LARVA, XENO_CASTE_PREDALIEN_LARVA)
-			remains.icon_state = "larva_gib_corpse"
-		else
-			remains.icon_state = "gibbed-a-corpse"
+			icon_path = 'icons/mob/xenos/larva.dmi'
+
+	remains.icon_state = gib_state
+	remains.icon = icon_path
 
 	check_blood_splash(35, BURN, 65, 2) //Some testing numbers. 35 burn, 65 chance.
 
@@ -170,8 +176,12 @@
 		icon_path = 'icons/mob/xenos/xenomorph_48x48.dmi'
 	switch(caste.caste_type)
 		if(XENO_CASTE_RUNNER)
+			icon_path = 'icons/mob/xenos/xenomorph_64x64.dmi'
 			to_flick = "gibbed-a-runner"
+		if(XENO_CASTE_BOILER)
+			to_flick = "gibbed-a-boiler"
 		if(XENO_CASTE_LARVA, XENO_CASTE_PREDALIEN_LARVA)
+			icon_path = 'icons/mob/xenos/larva.dmi'
 			to_flick = "larva_gib"
 	new /obj/effect/overlay/temp/gib_animation/xeno(loc, src, to_flick, icon_path)