UMCPHandler_DeleteNodeFromGraph - Refactoring Notes

What was done

Converted from JSON output (FJsonObject*) to plain-text output (FStringBuilderBase&).
MCPFetcher now receives Result (the FStringBuilderBase) as its error callback, so path resolution errors go directly to the caller as plain text.
Removed the three Result->SetStringField calls that echoed nodeClass/nodeTitle/graph back. The output now just confirms the deletion with a single line.
Removed both UE_LOG calls.
Error messages for protected entry nodes now go through MCPErrorCallback(Result) instead of MCPUtils::MakeErrorJson.
Removed the #include "EdGraph/EdGraph.h" include since EdGraphNode.h pulls it in (matching the example handler pattern).

The entry-node protection logic is solid and the error messages are detailed and helpful, explaining why the deletion is refused and what the user should do instead.
MCPFetcher handles all the object resolution cleanly — the Node path parameter does all the work.
The handler is concise; the bulk of the code is the entry-node guards, which is appropriate.

I kept all three entry-node checks (UK2Node_FunctionEntry, UK2Node_Event, UK2Node_CustomEvent) as separate blocks with distinct error messages. They could be collapsed into one check, but the per-type messages are more informative.
UK2Node_CustomEvent inherits from UK2Node_Event, so the Cast<UK2Node_Event> check would catch custom events too. The current ordering (FunctionEntry, Event, CustomEvent) means the CustomEvent branch is unreachable. If the intent is to give a different message for custom events, the CustomEvent check should come before the Event check. I left the order as-is to minimize diff, but this is worth reviewing.
This handler operates on a single node. The coding standards mention batching where it makes sense. A batch-delete could be useful, but it changes the API signature, so I left it as single-node for now.