- oakplugin host: Win32 LoadLibraryExW/GetProcAddress/FreeLibrary
backend (LOAD_WITH_ALTERED_SEARCH_PATH so bundle-sibling DLLs
resolve), same dl_open/dl_sym/dlclose surface — the POSIX path is
untouched; OFX hosts now compile on Windows
- proxymanager: PATH split via std::env::split_paths (Windows ';'),
ffmpeg.exe name, Windows candidate locations; split logic unit
tested