Replaces the Exosuit Materials 2 experiment with one about equipping mechs rather than destroying them. (#80267)

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## About The Pull Request
Replaces "Exosuit Materials 2: Excessive Damage Test" with "Exosuit
Materials 2: Load Strain Test". Rather than building and then destroying
two exosuits, you now equip them with any two (compatible) main
equipment pieces. Once the experiment is done, you'll have two exosuits
still, so consider making exosuits that you can donate to other crew
afterwards.

Note that the exosuit *has* to be built by the crew. Round-start
exosuits (or those obtained through other means like the nuke ops'
uplink) will not work.
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## Why It's Good For The Game
The idea of creating and destroying a few rounds of mechs sounds like a
neat concept. But in practice, it burns through station resources for no
real good reason, and is somewhat antithetical to the idea of robotics
making mechs for other departments. With this change, you're still
required to make the two mechs if you want the discount, but now they'll
be available afterwards. If someone has requested a mech for their
department, for example, you can now accomplish that and part of this
experiment simultaneously.


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## Changelog

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🆑
add: Adds a new discount experiment for unlocking the combat exosuit
nodes - complete it by scanning two exosuits with equipment in the left
and right hand slots. This replaces the prior discount experiment about
destroying exosuits.
/🆑

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your name to the right of the first 🆑 if you want to overwrite your
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code/__DEFINES/traits/declarations.dm

@@ -820,6 +820,9 @@ Remember to update _globalvars/traits.dm if you're adding/removing/renaming trai
 /// Trait given to mechs that can have orebox functionality on movement
 #define TRAIT_OREBOX_FUNCTIONAL "orebox_functional"
 
+///A trait for mechs that were created through the normal construction process, and not spawned by map or other effects.
+#define TRAIT_MECHA_CREATED_NORMALLY "trait_mecha_created_normally"
+
 ///fish traits
 #define TRAIT_RESIST_EMULSIFY "resist_emulsify"
 #define TRAIT_FISH_SELF_REPRODUCE "fish_self_reproduce"

code/_globalvars/traits/_traits.dm

@@ -555,6 +555,9 @@ GLOBAL_LIST_INIT(traits_by_type, list(
 	/obj/vehicle = list(
 		"TRAIT_OREBOX_FUNCTIONAL" = TRAIT_OREBOX_FUNCTIONAL,
 	),
+	/obj/vehicle/sealed/mecha = list(
+		"TRAIT_MECHA_CREATED_NORMALLY" = TRAIT_MECHA_CREATED_NORMALLY
+	),
 	/turf = list(
 		"TRAIT_CHASM_STOPPED" = TRAIT_CHASM_STOPPED,
 		"TRAIT_FIREDOOR_STOP" = TRAIT_FIREDOOR_STOP,

code/modules/experisci/experiment/experiments.dm

@@ -333,12 +333,22 @@
 	var/found_percent = round((target.get_integrity() / target.max_integrity) * 100)
 	return ..() && (found_percent <= (damage_percent + 2) && found_percent >= (damage_percent - 2))
 
-/datum/experiment/scanning/random/mecha_destroyed_scan
-	name = "Exosuit Materials 2: Excessive Damage Test"
-	description = "As an extension of testing exosuit damage results, scanning examples of complete structural failure will accelerate our material stress simulations."
-	possible_types = list(/obj/structure/mecha_wreckage)
+/datum/experiment/scanning/random/mecha_equipped_scan
+	name = "Exosuit Materials 2: Load Strain Test"
+	description = "Exosuit equipment places unique strain upon the structure of the vehicle. Scan exosuits you have assembled from your exosuit fabricator and fully equipped to accelerate our structural stress simulations."
+	possible_types = list(/obj/vehicle/sealed/mecha)
 	total_requirement = 2
 
+/datum/experiment/scanning/random/mecha_equipped_scan/final_contributing_index_checks(atom/target, typepath)
+	var/obj/vehicle/sealed/mecha/stompy = target
+	if(!istype(stompy))
+		return FALSE //Not a mech
+	if(!HAS_TRAIT(stompy,TRAIT_MECHA_CREATED_NORMALLY))
+		return FALSE //Not hand-crafted
+	if(!(stompy.equip_by_category[MECHA_L_ARM] && stompy.equip_by_category[MECHA_R_ARM]))
+		return FALSE //Both arms need be filled
+	return ..()
+
 /// Scan for organs you didn't start the round with
 /datum/experiment/scanning/people/novel_organs
 	name = "Human Field Research: Divergent Biology"

code/modules/research/techweb/all_nodes.dm

@@ -2011,7 +2011,7 @@
 		"mech_proj_armor",
 	)
 	required_experiments = list(/datum/experiment/scanning/random/mecha_damage_scan)
-	discount_experiments = list(/datum/experiment/scanning/random/mecha_destroyed_scan = 5000)
+	discount_experiments = list(/datum/experiment/scanning/random/mecha_equipped_scan = 5000)
 	research_costs = list(TECHWEB_POINT_TYPE_GENERIC = 10000)
 
 /datum/techweb_node/mech_scattershot

code/modules/vehicles/mecha/equipment/tools/work_tools.dm

@@ -392,6 +392,8 @@
 	if(markone.name != initial(markone.name))
 		newmech.name = markone.name
 	markone.wreckage = FALSE
+	if(HAS_TRAIT(markone, TRAIT_MECHA_CREATED_NORMALLY))
+		ADD_TRAIT(newmech, TRAIT_MECHA_CREATED_NORMALLY, newmech)
 	qdel(markone)
 	playsound(get_turf(newmech),'sound/items/ratchet.ogg',50,TRUE)
 

code/modules/vehicles/mecha/mecha_construction_paths.dm

@@ -33,6 +33,7 @@
 	var/obj/item/mecha_parts/chassis/parent_chassis = parent
 	mech.CheckParts(parent_chassis.contents)
 	SSblackbox.record_feedback("tally", "mechas_created", 1, mech.name)
+	ADD_TRAIT(mech, TRAIT_MECHA_CREATED_NORMALLY, mech)
 	QDEL_NULL(parent)
 
 // Default proc to generate mech steps.