add missing pilot suit assembly (#20995)

This PR adds in the missing construction recipe for the pilot hardsuit
assembly, which wasn't present in the mechatronic fabricator.

There was already a recipe in the circuit imprinter for the pilot suit
central control board here:
<img width="491" height="267" alt="image"
src="https://github.com/user-attachments/assets/aaeed072-75e5-4c94-a98e-9e1839939e06"
/>

However, no such assembly existed in the exosuit fabricator: 
<img width="508" height="329" alt="image"
src="https://github.com/user-attachments/assets/21eca010-8a09-4848-843f-e9b1aab0546e"
/>

And while the code implied it was possible to make a pilot suit by using
the pilot circuit board on an EVA suit assembly, it would instead make
an EVA suit.
<img width="315" height="183" alt="image"
src="https://github.com/user-attachments/assets/167889a4-f04a-4415-a3eb-77988f546649"
/>

So this PR adds the ability to make the pilot hardsuit assemblies
directly, allowing for the pilot suit to be made using the circuit board
that already existed as a roundstart hardsuit option.

code/modules/research/designs/mechfab/hardsuit/rigs.dm

@@ -17,6 +17,11 @@
 	desc = "An assembly for light rig that is desiged for repairs and maintenance to the outside of habitats and vessels."
 	build_path = /obj/item/rig_assembly/eva
 
+/datum/design/rig/eva/pilot
+	name = "pilot Suit Control Module Assembly"
+	desc = "An assembly for a light hardsuit that is designed for pilots."
+	build_path = /obj/item/rig_assembly/eva/pilot
+
 /datum/design/rig/industrial
 	name = "Industrial Suit Control Module Assembly"
 	desc = "An assembly for a heavy, powerful rig used by construction crews and mining corporations."