Marshal impl

Registry / MarshalMeta / Overload.

📄️MarshalMeta and Writers

Il2Cpp: marshal/MarshalMeta.cpp, marshal/MarshalDefs.h

📄️MethodOverloadResolver Implementation

Il2Cpp: marshal/MethodOverloadResolver.cpp

📄️Implementation — Marshal (`impl/marshal/`)

This directory describes Registry, MarshalMeta, and Overload C++/C# structures and call chains. Type conversion and LuaMarshalAs] rules are in [../../spec/marshal/.

📄️ObjectRegistry / StructRegistry

Il2Cpp: marshal/ObjectRegistry.cpp, marshal/StructRegistry.cpp