docs(changelog): reflect cog producer, cross-language test, Windows fixes

Update the Unreleased entry: calibration service is now complete across both
model paths (transformer .npz + cog safetensors via cog_calibrate.py) with
cross-language Python->Rust integration test; add the Windows cross-platform
build fixes (worldmodel cfg(unix), bfld CRLF) — 2682 workspace tests green/0
fail on Windows.

Co-Authored-By: claude-flow <ruv@ruv.net>