Initial commit: Item Interaction Ecosystem plugin (UE5.7)

Server-authoritative, data-driven item/inventory/interaction/carry/equipment/
world-slot/placement/crafting framework. 8 modules, compiles against UE 5.7.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Source/ItemCore/Public/ItemEnums.h

@@ -0,0 +1,95 @@
+// Copyright ExByte Studios. Item Interaction Ecosystem.
+
+#pragma once
+
+#include "CoreMinimal.h"
+#include "ItemEnums.generated.h"
+
+/**
+ * Where an item instance currently lives (section 5).
+ * Every state transition is validated server-side through the transaction layer.
+ */
+UENUM(BlueprintType)
+enum class EItemLocationType : uint8
+{
+	None,
+	World,
+	Inventory,
+	Container,
+	Held,
+	Equipped,
+	PlacementPreview,
+	Installed,
+	NestedContainer
+};
+
+/** Per-property replication scope (section 22). */
+UENUM(BlueprintType)
+enum class EItemPropertyReplicationPolicy : uint8
+{
+	None,
+	OwnerOnly,
+	Everyone,
+	NearbyOnly,
+	ServerOnly
+};
+
+/** How an item is currently carried/equipped on a character (section 11). */
+UENUM(BlueprintType)
+enum class EHeldItemMode : uint8
+{
+	None,
+	EquippedFromInventory,
+	CarryAttached,
+	CarryPhysicsHandle,
+	PlacementPreview
+};
+
+/** High level interaction mode resolved per option (section 8.5). */
+UENUM(BlueprintType)
+enum class EItemInteractionMode : uint8
+{
+	None,
+
+	InstantPickup,
+	OpenLootUI,
+	PickupToInventory,
+	EquipFromWorld,
+	EquipFromInventory,
+
+	CarryAttached,
+	CarryPhysicsHandle,
+	DropHeldItem,
+
+	Inspect,
+	Use,
+	UseHeldOnTarget,
+	Combine,
+
+	StartPlacement,
+	ConfirmPlacement,
+	CancelPlacement,
+
+	InstallIntoWorldSlot,
+	RemoveFromWorldSlot,
+
+	TransferContainerItem,
+	SplitStack,
+	MergeStack
+};
+
+/** Container layout / role (section 7.2). */
+UENUM(BlueprintType)
+enum class EInventoryContainerType : uint8
+{
+	SlotList,
+	Grid,
+	Equipment,
+	Hotbar,
+	VehicleCargo,
+	LootBox,
+	KeyRing,
+	Wallet,
+	CraftingInput,
+	CraftingOutput
+};