Platform UserInterface PackInitialize/PackSingletons (40250 bootstrap, on-disk dbname resolution), EterBase/FileLoader.cpp mirror, mtpack40250 backend behind asset_io's pack:// scheme and a Metin2Pack node. port_eterpack_test now registers through PackInitialize. Nothing reads pack:// at runtime yet; port-map stays TODO. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>