move the internal preview to canvas (#18930)

* move the internal preview to canvas

* use a helper

* basic readme prep

* .

* .

* transform  better

* byond can't handle icon states of large files...

* move fully to the rust version

* fix typing

* just wtf. NO

* fix the legacy path

* keep it all centralized

* tiny oversight

* unit test rewrite

* rename

* fix bad layering

* fixes a bunch of layering issues

* artifact

* move crash to log_runtime

* missing overlay warning

* why not

code/modules/asset_cache/assets/spritesheets/vending.dm

@@ -22,7 +22,7 @@
 
 		var/datum/universal_icon/I
 
-		var/icon_states_list = cached_icon_states(icon_file)
+		var/icon_states_list = icon_states_fast(icon_file)
 		if(icon_state in icon_states_list)
 			I = uni_icon(icon_file, icon_state, SOUTH)
 			var/c = initial(item.color)

code/modules/asset_cache/assets/spritesheets/vore.dm

@@ -1,15 +0,0 @@
-/datum/asset/spritesheet/vore
-	name = "vore"
-
-/datum/asset/spritesheet/vore/create_spritesheets()
-	var/icon/downscaled = icon('icons/mob/screen_full_vore_list.dmi') // preserving save data
-	downscaled.Scale(240, 240)
-	InsertAll("", downscaled)
-
-/datum/asset/spritesheet/vore_fixed //This should be getting loaded in the TGUI vore panel but the game refuses to do so, for some reason. It only loads the vore spritesheet.
-	name = "fixedvore"
-
-/datum/asset/spritesheet/vore_fixed/create_spritesheets() // preserving save data
-	var/icon/downscaledVF = icon('icons/mob/screen_full_vore.dmi')
-	downscaledVF.Scale(240, 240)
-	InsertAll("", downscaledVF)