Changelog Update

Codex CLI subprocesses again inherit env vars like LD_LIBRARY_PATH/DYLD_LIBRARY_PATH to avoid runtime issues. As explained in #8945, failure to pass along these environment variables to subprocesses that expect them (notably GPU-related ones), was causing 10x+ performance regressions! Special thanks to @johnzfitch for the detailed investigation and write-up in #8945. (#8951)