Adds gladiuses (gladii?) (#93631)

## About The Pull Request

Adds the Gladius alongside its scabbard. Replaces undead roman
legionarries' claymores with gladii.
<img width="152" height="105" alt="image"
src="https://github.com/user-attachments/assets/fdd21960-0f73-4564-b381-7044838a0f51"
/>
<img width="194" height="165" alt="image"
src="https://github.com/user-attachments/assets/a3f602e1-9ce6-4ded-b40d-d7088da292c9"
/>
<img width="136" height="133" alt="image"
src="https://github.com/user-attachments/assets/e8105ba3-d1e5-42cb-86e5-16db6edd56f7"
/>


## Why It's Good For The Game

This started as me thinking "hmmm those guys shouldn't have longswords"
and so I gave them the gladius, the famous standard issue foot soldier
weapon for the roman army. It's better in that it's more historically
accurate, which is definitely something everyone cares about a lot.

## Changelog
🆑
add: Roman skeletons now have Roman swords.
/🆑

---------

Co-authored-by: die <96586172+grungussuss@users.noreply.github.com>

code/modules/antagonists/wizard/equipment/artefact.dm

@@ -304,7 +304,7 @@
 	uniform = /obj/item/clothing/under/costume/roman
 	shoes = /obj/item/clothing/shoes/roman
 	back = /obj/item/spear
-	r_hand = /obj/item/claymore
+	belt = /obj/item/storage/belt/sheath/gladius
 	l_hand = /obj/item/shield/roman
 
 /datum/outfit/roman/pre_equip(mob/living/carbon/human/H, visuals_only)