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/ItemInventory/Public/InventoryContainer.h

@@ -0,0 +1,74 @@
+// Copyright ExByte Studios. Item Interaction Ecosystem.
+
+#pragma once
+
+#include "CoreMinimal.h"
+#include "GameplayTagContainer.h"
+#include "ItemEnums.h"
+#include "InventoryContainer.generated.h"
+
+/**
+ * Metadata describing one container owned by an inventory (section 7.2).
+ *
+ * NOTE (design deviation from the TЗ sketch): the actual item entries do NOT live
+ * inside the container struct. They live in the component's single
+ * FReplicatedInventoryList, tagged with this ContainerId. A FastArraySerializer
+ * only delta-replicates correctly as a direct UPROPERTY, so nesting one inside a
+ * replicated TArray<FInventoryContainer> would silently fall back to full-array
+ * replication. Keeping containers as lightweight metadata fixes that (section 32).
+ */
+USTRUCT(BlueprintType)
+struct ITEMINVENTORY_API FInventoryContainer
+{
+	GENERATED_BODY()
+
+	UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = "Container")
+	FGuid ContainerId;
+
+	/** Logical identity, e.g. Container.Backpack / Container.Hotbar / Container.Vehicle.Cargo. */
+	UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = "Container")
+	FGameplayTag ContainerTag;
+
+	UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = "Container")
+	EInventoryContainerType Type = EInventoryContainerType::SlotList;
+
+	UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = "Container")
+	int32 Width = 0;
+
+	UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = "Container")
+	int32 Height = 0;
+
+	/** Used by SlotList/Equipment/Hotbar; for Grid types capacity is Width*Height. */
+	UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = "Container")
+	int32 MaxSlots = 0;
+
+	UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = "Container")
+	float MaxWeight = 0.f;
+
+	UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = "Container")
+	FGameplayTagContainer AcceptedItemTags;
+
+	UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = "Container")
+	FGameplayTagContainer BlockedItemTags;
+
+	/** Set when this container lives inside another item (a backpack/pouch item) - section 7. */
+	UPROPERTY(BlueprintReadOnly, Category = "Container")
+	FGuid OwnerItemInstanceId;
+
+	FInventoryContainer() = default;
+
+	bool IsNested() const { return OwnerItemInstanceId.IsValid(); }
+
+	/** Number of addressable slots in this container (0 = unlimited weight-gated list). */
+	int32 GetSlotCount() const
+	{
+		if (Type == EInventoryContainerType::Grid)
+		{
+			return FMath::Max(0, Width) * FMath::Max(0, Height);
+		}
+		return FMath::Max(0, MaxSlots);
+	}
+
+	bool HasSlotLimit() const { return GetSlotCount() > 0; }
+	bool HasWeightLimit() const { return MaxWeight > 0.f; }
+};