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/ItemWorld/Public/WorldItemSlotComponent.h

@@ -0,0 +1,83 @@
+// Copyright ExByte Studios. Item Interaction Ecosystem.
+
+#pragma once
+
+#include "CoreMinimal.h"
+#include "Components/ActorComponent.h"
+#include "GameplayTagContainer.h"
+#include "ItemInstanceData.h"
+#include "WorldItemSlotComponent.generated.h"
+
+DECLARE_DYNAMIC_MULTICAST_DELEGATE(FOnWorldSlotChanged);
+
+/** Replicated state of a world slot's contents (section 14). */
+USTRUCT()
+struct FWorldSlotInstalledState
+{
+	GENERATED_BODY()
+
+	UPROPERTY()
+	bool bHasItem = false;
+
+	UPROPERTY()
+	FItemInstanceData Item;
+};
+
+/**
+ * A socket on a world object that accepts an installed item (section 14):
+ * Vehicle.Socket.Battery, Generator.Socket.Fuel, Door.Socket.BarricadePlank,
+ * Trap.Socket.Bait, etc. One component per slot.
+ */
+UCLASS(ClassGroup = (Interaction), meta = (BlueprintSpawnableComponent))
+class ITEMWORLD_API UWorldItemSlotComponent : public UActorComponent
+{
+	GENERATED_BODY()
+
+public:
+	UWorldItemSlotComponent();
+
+	virtual void GetLifetimeReplicatedProps(TArray<FLifetimeProperty>& OutLifetimeProps) const override;
+
+	/** This slot's identity; items list it in CompatibleWorldSlots to fit. */
+	UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = "World Slot")
+	FGameplayTag SlotTag;
+
+	/** Optional extra gate; empty = accept anything whose CompatibleWorldSlots has SlotTag. */
+	UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = "World Slot")
+	FGameplayTagContainer AcceptedItemTags;
+
+	UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = "World Slot")
+	FName AttachSocketName = NAME_None;
+
+	UPROPERTY(BlueprintAssignable, Category = "World Slot")
+	FOnWorldSlotChanged OnSlotChanged;
+
+	UFUNCTION(BlueprintPure, Category = "World Slot")
+	bool IsOccupied() const { return InstalledItem.bHasItem; }
+
+	UFUNCTION(BlueprintPure, Category = "World Slot")
+	bool CanInstall(const FItemInstanceData& Item) const;
+
+	UFUNCTION(BlueprintPure, Category = "World Slot")
+	FItemInstanceData GetInstalledItem() const { return InstalledItem.Item; }
+
+	/** Server: install an item. ProvidedVisual (e.g. a carried actor) is reused if given. */
+	bool InstallItem(const FItemInstanceData& Item, AActor* ProvidedVisual = nullptr);
+
+	/** Server: remove and return the installed item. */
+	bool RemoveItem(FItemInstanceData& OutItem);
+
+protected:
+	UPROPERTY(ReplicatedUsing = OnRep_InstalledItem)
+	FWorldSlotInstalledState InstalledItem;
+
+	/** Server-spawned visual for the installed item (if not provided externally). */
+	UPROPERTY(Replicated)
+	TObjectPtr<AActor> InstalledVisual = nullptr;
+
+	UFUNCTION()
+	void OnRep_InstalledItem();
+
+	USceneComponent* GetAttachTarget() const;
+	bool HasAuthority() const;
+};