docs: publish Dragon remesh showcase

[loonghao]

Summary

• replace the ZBrush showcase image with the real 115,364-face PolyFrame capture
• publish exact import, face-count, bake, ZRemesh, thread-serialization, and export acceptance steps in English and Chinese
• preserve Artec 3D CC BY 4.0 attribution and the existing real Maya cross-DCC evidence

Validation

• npm run docs:build
• desktop Chrome render at 1440 px
• mobile Chrome render at 390 px