docs: add structured Version History (0.0.02 / engine 0.0.07 release notes)

Categorized highlights (Ease of Use / Model Support / Performance / New Features /
Stability) for the 0.0.02 release, in both README.md (EN) and README_zh.md (中文).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>