Adds a Tretian Guild mantle (#19576)

![image](https://i.imgur.com/sWeaojJ.gif)
![image](https://i.imgur.com/jaP6LxN.gif)
![image](https://i.imgur.com/IER42Sl.gif)
Requires sign-off by Vaurca lore. @desvenlafaxine

code/modules/client/preference_setup/loadout/items/xeno/vaurca.dm

@@ -382,3 +382,13 @@
 	whitelisted = list(SPECIES_VAURCA_BREEDER)
 	sort_category = "Xenowear - Vaurca"
 	flags = GEAR_HAS_NAME_SELECTION | GEAR_HAS_DESC_SELECTION | GEAR_HAS_COLOR_SELECTION
+
+/datum/gear/suit/unathi_mantle_tret
+	display_name = "tretian guild mantle"
+	description = "A yellow mantle, worn by Tretian Guild workers in the Izweski Hegemony."
+	path = /obj/item/clothing/accessory/poncho/unathimantle/tretian
+	cost = 1
+	sort_category = "Xenowear - Vaurca"
+	flags = GEAR_HAS_COLOR_SELECTION
+	whitelisted = list(SPECIES_VAURCA_WORKER, SPECIES_VAURCA_WARRIOR, SPECIES_VAURCA_BULWARK, SPECIES_UNATHI)
+	culture_restriction = list(/singleton/origin_item/culture/klax)

code/modules/clothing/under/accessories/xeno/unathi.dm

@@ -193,6 +193,20 @@
 	megacorporation's aquacultural expansions on Ouerea - bringing an end to the famine, though some say at the price of the guild's soul."
 	worn_overlay = "fishingleague"
 
+/obj/item/clothing/accessory/poncho/unathimantle/tretian
+	name = "tretian guild mantle"
+	desc = "The cured hide and skin of a large beast, dyed in the acidic yellow of the Tretian Guild. These mantles are reserved for full-fledged guildsmen, as a sign of \
+	their position in the guild."
+	desc_extended = "The Tretian Guild is the only Unathi guild with a K'lax majority. \
+	Established in Tret, the guild specializes in operating and maintaining the large-scale manufacturing operations of the factory-planet. \
+	In a controversial move, the Tretian Guild expanded its operations beyond Tret in mid-2466, acting as strikebreakers and supplemental workers \
+	for operations where workers of other guilds may be unwilling or unable to fulfill their duties."
+	worn_overlay = "tretianguild"
+	sprite_sheets = list(
+		BODYTYPE_VAURCA = 'icons/mob/species/vaurca/suit.dmi',
+		BODYTYPE_VAURCA_BULWARK = 'icons/mob/species/bulwark/suit.dmi'
+	)
+
 /obj/item/clothing/accessory/poncho/rockstone
 	name = "rockstone cape"
 	desc = "A cape seen exclusively on nobility. The chain is adorned with precious, multi-color stones, hence its name."

html/changelogs/SimpleMaroon-tretianguildmantle.yml

@@ -0,0 +1,58 @@
+################################
+# Example Changelog File
+#
+# Note: This file, and files beginning with ".", and files that don't end in ".yml" will not be read. If you change this file, you will look really dumb.
+#
+# Your changelog will be merged with a master changelog. (New stuff added only, and only on the date entry for the day it was merged.)
+# When it is, any changes listed below will disappear.
+#
+# Valid Prefixes:
+#   bugfix
+#     - (fixes bugs)
+#   wip
+#     - (work in progress)
+#   qol
+#     - (quality of life)
+#   soundadd
+#     - (adds a sound)
+#   sounddel
+#     - (removes a sound)
+#   rscadd
+#     - (adds a feature)
+#   rscdel
+#     - (removes a feature)
+#   imageadd
+#     - (adds an image or sprite)
+#   imagedel
+#     - (removes an image or sprite)
+#   spellcheck
+#     - (fixes spelling or grammar)
+#   experiment
+#     - (experimental change)
+#   balance
+#     - (balance changes)
+#   code_imp
+#     - (misc internal code change)
+#   refactor
+#     - (refactors code)
+#   config
+#     - (makes a change to the config files)
+#   admin
+#     - (makes changes to administrator tools)
+#   server
+#     - (miscellaneous changes to server)
+#################################
+
+# Your name.
+author: SimpleMaroon
+
+# Optional: Remove this file after generating master changelog.  Useful for PR changelogs that won't get used again.
+delete-after: True
+
+# Any changes you've made.  See valid prefix list above.
+# INDENT WITH TWO SPACES.  NOT TABS.  SPACES.
+# SCREW THIS UP AND IT WON'T WORK.
+# Also, this gets changed to [] after reading.  Just remove the brackets when you add new shit.
+# Please surround your changes in  double quotes ("). It works without them, but if you use certain characters it screws up compiling. The quotes will not show up in the changelog.
+changes:
+  - imageadd: "Added a Tretian Guild mantle for Vaurcae and Unathi to wear; it can be found under the Vaurca Xenowear tab."