BlueprintMCP TODO

When compiling blueprints, always check for errors properly. Many handlers call FKismetEditorUtilities::CompileBlueprint and assume success without checking. The validation handler (MCPHandlers_Validation.h) already has proper error collection logic — all compile sites should follow that pattern.
Add FindBlueprintGraph to UMCPAssetFinder: load blueprint, URL-decode graph name, search all graphs by name, return UEdGraph* or nullptr with error. Currently ~10 handlers duplicate this 25-line pattern (see MCPHandlers_Mutation.h:186-210 for a typical example).