docs: 增加 OPC 关键词，修复图片布局和比例问题

- 中英文 README 标题和描述增加 OPC（一人公司）关键词
- 修复 GitHub 不支持的 flex 布局，改为内联图片并排显示
- 调整 monetize 截图宽度从 50% 到 30%（竖屏截图比例更合理）
- 同步英文版 Publish 渠道图片为 channel-cn.png

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Update README_CN.md

fix: fix agent ui (#480)

feat(agent): add public share, forward and frontend rating UI (#461)

fix: action card persistence and chat status improvements (#447)

fix(web): web1218 Some issues (#413)

fix(web): The content is ready and you will be redirected to the publ…

…ishing page shortly. (#394)

docs(readme): add 'what's news' (#351)

fix(media): handle full URL paths in media service (#322)

feat(material): Material controller with URL handling (#256)