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/ItemInteraction/Public/InteractionAction.h

@@ -0,0 +1,65 @@
+// Copyright ExByte Studios. Item Interaction Ecosystem.
+
+#pragma once
+
+#include "CoreMinimal.h"
+#include "UObject/Object.h"
+#include "GameplayTagContainer.h"
+#include "ItemEnums.h"
+#include "InteractionTypes.h"
+#include "InteractionAction.generated.h"
+
+/**
+ * A single interaction verb, authored as an instanced object on an
+ * InteractableComponent (section 16). This is the Blueprint-extensible path:
+ * built-in modes are also handled directly by the interaction component, but
+ * any custom verb can be added here without C++.
+ *
+ * CanExecute/Execute must be safe to run on the server. CanExecute may also run
+ * on the client for predictive UI, so it must not mutate state.
+ */
+UCLASS(Abstract, Blueprintable, EditInlineNew, DefaultToInstanced, CollapseCategories)
+class ITEMINTERACTION_API UInteractionAction : public UObject
+{
+	GENERATED_BODY()
+
+public:
+	UPROPERTY(EditDefaultsOnly, BlueprintReadOnly, Category = "Action")
+	FGameplayTag ActionTag;
+
+	UPROPERTY(EditDefaultsOnly, BlueprintReadOnly, Category = "Action")
+	FText DisplayText;
+
+	UPROPERTY(EditDefaultsOnly, BlueprintReadOnly, Category = "Action")
+	EItemInteractionMode Mode = EItemInteractionMode::Use;
+
+	UPROPERTY(EditDefaultsOnly, BlueprintReadOnly, Category = "Action")
+	int32 Priority = 300;
+
+	UPROPERTY(EditDefaultsOnly, BlueprintReadOnly, Category = "Action")
+	bool bRequiresHold = false;
+
+	UPROPERTY(EditDefaultsOnly, BlueprintReadOnly, Category = "Action")
+	float HoldDuration = 0.f;
+
+	UPROPERTY(EditDefaultsOnly, BlueprintReadOnly, Category = "Action")
+	FInteractionExecutionData Execution;
+
+	UPROPERTY(EditDefaultsOnly, BlueprintReadOnly, Category = "Action")
+	TArray<FInteractionRequirement> Requirements;
+
+	/** Pure check: are all requirements satisfied? Writes the first failure reason. */
+	UFUNCTION(BlueprintNativeEvent, BlueprintCallable, Category = "Action")
+	bool CanExecute(const FInteractionContext& Context, FText& OutDisabledReason) const;
+	virtual bool CanExecute_Implementation(const FInteractionContext& Context, FText& OutDisabledReason) const;
+
+	/** Server-authoritative effect. */
+	UFUNCTION(BlueprintNativeEvent, BlueprintCallable, Category = "Action")
+	void Execute(const FInteractionContext& Context);
+	virtual void Execute_Implementation(const FInteractionContext& Context);
+
+	/** Turns this action into a UI option for the given context. */
+	FInteractionOption BuildOption(const FInteractionContext& Context) const;
+
+	virtual UWorld* GetWorld() const override;
+};