This implementation replaces previous version by centralizing the locale-to-codepage mapping logic within the core StringConvert module. This approach improves portability by using standard iconv encoding names, and provides a fallback mechanism to the default 7-Zip conversion behavior if the requested charset is unavailable. Additionally, this commit introduces a standalone unit test harness, TEST_LegacyMapping.cpp, to verify the cross-locale codepage mapping logic independently of the full archive processing pipeline.
