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/MCPMaterialLibrary.h

@@ -0,0 +1,28 @@
+#pragma once
+
+#include "CoreMinimal.h"
+#include "Kismet/BlueprintFunctionLibrary.h"
+#include "MCPMaterialLibrary.generated.h"
+
+class UMaterialExpression;
+class UMaterial;
+class UMaterialFunction;
+
+UCLASS()
+class UEBLUEPRINTMCPEDITOR_API UMCPMaterialLibrary : public UBlueprintFunctionLibrary
+{
+    GENERATED_BODY()
+
+public:
+    UFUNCTION(BlueprintCallable, Category = "MCP|Material")
+    static TArray<UMaterialExpression*> GetMaterialExpressions(UObject* MaterialOrFunction);
+
+    UFUNCTION(BlueprintCallable, Category = "MCP|Material")
+    static UMaterialExpression* FindMaterialExpression(UObject* MaterialOrFunction, const FString& NodeId);
+
+    UFUNCTION(BlueprintCallable, Category = "MCP|Material")
+    static FString DumpMaterialGraphToJson(UObject* MaterialOrFunction);
+
+    UFUNCTION(BlueprintCallable, Category = "MCP|Material")
+    static FString ConnectMaterialExpressionsRaw(UObject* MaterialOrFunction, UMaterialExpression* FromExpression, const FString& FromOutput, UMaterialExpression* ToExpression, const FString& ToInput);
+};