Fix two handed items from bricking hands when a user changes species (#29573)

* create flag to skip species transform reequip

* add to bitfield and change to 1<<15

code/__DEFINES/flags.dm

@@ -14,6 +14,7 @@
 #define NODECONSTRUCT			(1<<9)
 #define EARBANGPROTECT			(1<<10)
 #define HEADBANGPROTECT			(1<<11)
+#define SKIP_TRANSFORM_REEQUIP	(1<<15)		// This flag makes items be skipped when a user transforms species.
 
 #define BLOCK_GAS_SMOKE_EFFECT	(1<<12)	// blocks the effect that chemical clouds would have on a mob --glasses, mask and helmets ONLY!
 #define THICKMATERIAL 			(1<<12)	//prevents syringes, parapens and hypos if the external suit or helmet (if targeting head) has this flag. Example: space suits, biosuit, bombsuits, thick suits that cover your body. (NOTE: flag shared with BLOCK_GAS_SMOKE_EFFECT)

code/_globalvars/bitfields.dm

@@ -101,6 +101,7 @@ DEFINE_BITFIELD(flags, list(
 	"HANDSLOW" = HANDSLOW,
 	"CONDUCT" = CONDUCT,
 	"ABSTRACT" = ABSTRACT,
+	"SKIP_TRANSFORM_REEQUIP" = SKIP_TRANSFORM_REEQUIP,
 	"ON_BORDER" = ON_BORDER,
 	"PREVENT_CLICK_UNDER" = PREVENT_CLICK_UNDER,
 	"NODECONSTRUCT" = NODECONSTRUCT,

code/datums/components/two_handed.dm

@@ -410,7 +410,7 @@
 	name = "offhand"
 	icon_state = "offhand"
 	w_class = WEIGHT_CLASS_HUGE
-	flags = ABSTRACT | NODROP
+	flags = ABSTRACT | NODROP | SKIP_TRANSFORM_REEQUIP
 	resistance_flags = INDESTRUCTIBLE | LAVA_PROOF | FIRE_PROOF | UNACIDABLE | ACID_PROOF
 	var/wielded = FALSE // Off Hand tracking of wielded status
 

code/modules/mob/living/carbon/human/human_mob.dm

@@ -1185,6 +1185,8 @@
 	for(var/thing in thing_to_check)
 		var/obj/item/I = get_item_by_slot(thing)
 		if(I)
+			if(I.flags & SKIP_TRANSFORM_REEQUIP)
+				continue
 			kept_items[I] = thing
 			item_flags[I] = I.flags
 			I.flags = 0 // Temporary set the flags to 0