Why this change was needed:
The RapidProxy sponsorship ended, and NodeMaven refreshed its banner and moved
to per-surface tracking links.
What changed:
- Remove the RapidProxy sponsor block from README.md and README_zh-CN.md, and
delete assets/sponsors/rapidproxy-banner.png.
- Update the NodeMaven banner (assets/sponsors/nodemaven-banner.png) and point
both README links to the GitHub-surface URL go.nodemaven.com/webclawgh. Text
unchanged.
* docs: add Simplified Chinese README (README_zh-CN.md)
* chore: add README language switcher and FUNDING sponsor link
* docs: unlink Firecrawl anchor in zh README and align switcher link style
