- README.md restored to Chinese (the default for Huasheng's primary audience)
- Added language toggle at top-left: English link in Chinese README, Chinese link in English README
- Added bilingual tagline in Chinese README hero
- Added demos/hero-animation-v9.mp4 (10MB) as hero animation, fallback to w3 GIF
- English README created as README.en.md with same demo gallery assets
Fixes: prior commit mistakenly replaced Chinese README entirely with English version
