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/FuelTankComponent.h

@@ -0,0 +1,48 @@
+// Copyright ExByte Studios. Item Interaction Ecosystem.
+
+#pragma once
+
+#include "CoreMinimal.h"
+#include "Components/ActorComponent.h"
+#include "ItemInteractionInterfaces.h"
+#include "FuelTankComponent.generated.h"
+
+DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FOnFuelChanged, float, NewFuel);
+
+/**
+ * A fuel reservoir on a world object (generator, vehicle) that accepts fuel poured
+ * from a held canister (section 15, 31.4). Implements IItemUseTarget for the
+ * "TransferFuel" result verb.
+ */
+UCLASS(ClassGroup = (Interaction), meta = (BlueprintSpawnableComponent))
+class ITEMWORLD_API UFuelTankComponent : public UActorComponent, public IItemUseTarget
+{
+	GENERATED_BODY()
+
+public:
+	UFuelTankComponent();
+
+	virtual void GetLifetimeReplicatedProps(TArray<FLifetimeProperty>& OutLifetimeProps) const override;
+
+	UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = "Fuel")
+	float MaxFuel = 40.f;
+
+	/** Max litres poured per single use action. */
+	UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = "Fuel")
+	float PourAmount = 10.f;
+
+	UPROPERTY(ReplicatedUsing = OnRep_Fuel, BlueprintReadOnly, Category = "Fuel")
+	float CurrentFuel = 0.f;
+
+	UPROPERTY(BlueprintAssignable, Category = "Fuel")
+	FOnFuelChanged OnFuelChanged;
+
+	//~ IItemUseTarget
+	virtual bool ReceiveHeldUse(FName ResultVerb, FItemInstanceData& HeldItem, AActor* Instigator) override;
+
+protected:
+	UFUNCTION()
+	void OnRep_Fuel();
+
+	bool HasAuthority() const;
+};