Unified, portable Unreal Engine MCP system plugin

Merge of the two project copies into one self-contained plugin (the superset:
variable_op + variables.py, full pcg_op runtime/declarative/preset ops, the
CreateWidgetFloatAnimation widget tool, and full Voxel graph authoring).

Made fully project- and machine-agnostic — no hardcoded paths:
- New src/projectPaths.js auto-detects the host .uproject (walk-up), project
  name, Editor build target, log file, and engine install (EngineAssociation
  via launcher manifest/registry, else installed-engine scan). All overridable
  via UE_* env vars.
- Rewired buildOrchestrator/insights/launcher/insightsExporter/server.js and the
  Python workers (cpp_scaffold, live_coding, apply_graph, console) off the old
  C:/Github/ihy, IHY*, E:/UE_Versions and UE_5.7 literals onto the resolver.
- Voxel made optional: Build.cs auto-detects the Voxel plugin (env
  UE_MCP_WITH_VOXEL override) and the C++ compiles to stubs under WITH_MCP_VOXEL,
  so the module builds in projects without Voxel; .uplugin marks Voxel optional.
- De-branded the agent-gateway and docs; scrubbed a leaked API key; excluded
  node_modules/Binaries/Intermediate/__pycache__/secrets from the repo.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Source/UEBlueprintMCPEditor/Public/UEBlueprintMCPEditor.h

@@ -0,0 +1,31 @@
+#pragma once
+
+#include "CoreMinimal.h"
+#include "Modules/ModuleManager.h"
+
+class FBlueprintEditor;
+class IInputProcessor;
+class UBlueprint;
+class UEdGraph;
+
+class FUEBlueprintMCPEditorModule : public IModuleInterface
+{
+public:
+    virtual void StartupModule() override;
+    virtual void ShutdownModule() override;
+
+private:
+    friend class FMCPZoneInputProcessor;
+
+    void RegisterMenus();
+    void NotifyBridgeStatus();
+    void ToggleMCPZoneMode(TWeakPtr<FBlueprintEditor> BlueprintEditor);
+    bool IsMCPZoneModeActive(TWeakPtr<FBlueprintEditor> BlueprintEditor) const;
+    bool TryCreateMCPZoneFromScreenDrag(const FVector2f& StartScreenPosition, const FVector2f& EndScreenPosition);
+    void CreateMCPZone(UEdGraph* Graph, UBlueprint* Blueprint, const FVector2f& GraphStart, const FVector2f& GraphEnd) const;
+    void RemoveMCPZones(UBlueprint* Blueprint) const;
+
+    bool bMCPZoneModeActive = false;
+    TWeakPtr<FBlueprintEditor> ActiveMCPZoneEditor;
+    TSharedPtr<IInputProcessor> MCPZoneInputProcessor;
+};