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/ItemDeveloper/Public/ItemDeveloperModule.h

@@ -0,0 +1,25 @@
+// Copyright ExByte Studios. Item Interaction Ecosystem.
+
+#pragma once
+
+#include "CoreMinimal.h"
+#include "Modules/ModuleManager.h"
+
+/**
+ * Editor-only tooling for the Item Ecosystem (section 27-28).
+ * Registers a "Item Ecosystem" menu under Tools with data validation. The full
+ * Item Ecosystem Editor (browser/filters/templates) is intended to be built on
+ * top of this as an Editor Utility Widget driving UItemDatabaseSubsystem.
+ */
+class FItemDeveloperModule : public IModuleInterface
+{
+public:
+	virtual void StartupModule() override;
+	virtual void ShutdownModule() override;
+
+private:
+	void RegisterMenus();
+	static void ValidateAllItems();
+	static void ExportItemsToCsv();
+	static void ReportMissingAssets();
+};