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/ItemInteractionActions.h

@@ -0,0 +1,72 @@
+// Copyright ExByte Studios. Item Interaction Ecosystem.
+
+#pragma once
+
+#include "CoreMinimal.h"
+#include "InteractionAction.h"
+#include "ItemInteractionActions.generated.h"
+
+/**
+ * Concrete interaction actions (section 16). These are the Blueprint-droppable
+ * authoring units: add one to an InteractableComponent's AvailableActions and the
+ * resolver/executor will surface and run it. Built-in modes are also dispatched
+ * directly by the interaction component, so both paths reach the same effect.
+ */
+
+UCLASS(meta = (DisplayName = "Action: Instant Pickup"))
+class ITEMINTERACTION_API UInteractionAction_InstantPickup : public UInteractionAction
+{
+	GENERATED_BODY()
+public:
+	UInteractionAction_InstantPickup();
+	virtual void Execute_Implementation(const FInteractionContext& Context) override;
+};
+
+UCLASS(meta = (DisplayName = "Action: Open Loot UI"))
+class ITEMINTERACTION_API UInteractionAction_OpenLootUI : public UInteractionAction
+{
+	GENERATED_BODY()
+public:
+	UInteractionAction_OpenLootUI();
+};
+
+UCLASS(meta = (DisplayName = "Action: Inspect"))
+class ITEMINTERACTION_API UInteractionAction_Inspect : public UInteractionAction
+{
+	GENERATED_BODY()
+public:
+	UInteractionAction_Inspect();
+	virtual void Execute_Implementation(const FInteractionContext& Context) override;
+};
+
+UCLASS(meta = (DisplayName = "Action: Combine"))
+class ITEMINTERACTION_API UInteractionAction_Combine : public UInteractionAction
+{
+	GENERATED_BODY()
+public:
+	UInteractionAction_Combine();
+};
+
+UCLASS(meta = (DisplayName = "Action: Transfer Container Item"))
+class ITEMINTERACTION_API UInteractionAction_TransferContainerItem : public UInteractionAction
+{
+	GENERATED_BODY()
+public:
+	UInteractionAction_TransferContainerItem();
+};
+
+UCLASS(meta = (DisplayName = "Action: Split Stack"))
+class ITEMINTERACTION_API UInteractionAction_SplitStack : public UInteractionAction
+{
+	GENERATED_BODY()
+public:
+	UInteractionAction_SplitStack();
+};
+
+UCLASS(meta = (DisplayName = "Action: Merge Stack"))
+class ITEMINTERACTION_API UInteractionAction_MergeStack : public UInteractionAction
+{
+	GENERATED_BODY()
+public:
+	UInteractionAction_MergeStack();
+};