Makes the mech repair droid unstackable + mech armor balance (tgstati…

…on#88789)

## About The Pull Request
alternative to tgstation#88776
Makes the repair droid unable to be stacked and reduces armor slots to 1
on station mechs except the phazon.

## Why It's Good For The Game

You can get to some pretty heavy duty values on certain mechs,
especially the durand, with a very intense rate of healing. This makes
those items unstackable.


![image](https://github.com/user-attachments/assets/714c48ca-f9a1-4452-bc25-9d20070f43be)


## Changelog

:cl:
balance: Reduces armor slots to 1 for all station built mechs except the
phazon.
balance: melee mech armor has been increased to 20 from 15.
balance: mech bullet and laser armor has both been increased to 15 from
10.
balance: You can no longer stack the repair droid on mechs.
/:cl:

code/modules/vehicles/mecha/combat/durand.dm

@@ -18,7 +18,7 @@
 		MECHA_R_ARM = 1,
 		MECHA_UTILITY = 3,
 		MECHA_POWER = 1,
-		MECHA_ARMOR = 3,
+		MECHA_ARMOR = 1,
 	)
 	var/obj/durand_shield/shield
 

code/modules/vehicles/mecha/combat/gygax.dm

@@ -18,7 +18,7 @@
 		MECHA_R_ARM = 1,
 		MECHA_UTILITY = 3,
 		MECHA_POWER = 1,
-		MECHA_ARMOR = 2,
+		MECHA_ARMOR = 1,
 	)
 	step_energy_drain = 4
 	can_use_overclock = TRUE

code/modules/vehicles/mecha/combat/honker.dm

@@ -57,7 +57,7 @@
 		MECHA_R_ARM = 1,
 		MECHA_UTILITY = 3,
 		MECHA_POWER = 1,
-		MECHA_ARMOR = 3,
+		MECHA_ARMOR = 2,
 	)
 
 /obj/vehicle/sealed/mecha/honker/dark/loaded

code/modules/vehicles/mecha/combat/savannah_ivanov.dm

@@ -35,7 +35,7 @@
 		MECHA_R_ARM = 1,
 		MECHA_UTILITY = 3,
 		MECHA_POWER = 1,
-		MECHA_ARMOR = 3,
+		MECHA_ARMOR = 1,
 	)
 	//no tax on flying, since the power cost is in the leap itself.
 	phasing_energy_drain = 0

code/modules/vehicles/mecha/equipment/mecha_equipment.dm

@@ -18,6 +18,8 @@
 	var/can_be_triggered = FALSE
 	///Whether the module is currently active
 	var/active = TRUE
+	///Can we stack multiple types of the same item?
+	var/unstackable = FALSE
 	///Label used in the ui next to the Activate/Enable/Disable buttons
 	var/active_label = "Status"
 	///Chassis power cell quantity used on activation
@@ -157,6 +159,13 @@
 				to_chat(user, span_warning("\The [mech]'s left arm is full![mech.equip_by_category[MECHA_R_ARM] || !mech.max_equip_by_category[MECHA_R_ARM] ? "" : " Try right arm!"]"))
 				return FALSE
 		return TRUE
+	if(unstackable)
+		var/list/obj/item/mecha_parts/mecha_equipment/contents = mech.equip_by_category[equipment_slot]
+		for(var/obj/equipment as anything in contents)
+			if(src.type == equipment.type)
+				to_chat(user, span_warning("You can't stack more of this item ontop itself!"))
+				return FALSE
+
 	if(length(mech.equip_by_category[equipment_slot]) == mech.max_equip_by_category[equipment_slot])
 		to_chat(user, span_warning("This equipment slot is already full!"))
 		return FALSE

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

@@ -173,7 +173,7 @@
 	armor_mod = /datum/armor/mecha_equipment_ccw_boost
 
 /datum/armor/mecha_equipment_ccw_boost
-	melee = 15
+	melee = 20
 
 /obj/item/mecha_parts/mecha_equipment/armor/antiproj_armor_booster
 	name = "Projectile Shielding"
@@ -184,8 +184,8 @@
 	armor_mod = /datum/armor/mecha_equipment_ranged_boost
 
 /datum/armor/mecha_equipment_ranged_boost
-	bullet = 10
-	laser = 10
+	bullet = 15
+	laser = 15
 
 ////////////////////////////////// REPAIR DROID //////////////////////////////////////////////////
 
@@ -196,6 +196,7 @@
 	icon_state = "repair_droid"
 	energy_drain = 50
 	range = 0
+	unstackable = TRUE
 	can_be_toggled = TRUE
 	active = FALSE
 	equipment_slot = MECHA_UTILITY