📝 docs: update model-provider document

[SpeedupMaster]

💻 变更类型 | Change Type

• ✨ feat
• 🐛 fix
• ♻️ refactor
• 💄 style
• 👷 build
• ⚡️ perf
• 📝 docs
• 🔨 chore

🔀 变更说明 | Description of Change

增加混元模型

📝 补充信息 | Additional Information

[vercel]

@SpeedupMaster is attempting to deploy a commit to the LobeChat Community Team on Vercel.

A member of the Team first needs to authorize it.

[lobehubbot]

👍 @SpeedupMaster

Thank you for raising your pull request and contributing to our Community
Please make sure you have followed our contributing guidelines. We will review it as soon as possible.
If you encounter any problems, please feel free to connect with us.
非常感谢您提出拉取请求并为我们的社区做出贡献，请确保您已经遵循了我们的贡献指南，我们会尽快审查它。
如果您遇到任何问题，请随时与我们联系。

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.50%. Comparing base (b0c3abc) to head (45f6c8e).
Report is 5 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##             main    #4181     +/-   ##
=========================================
  Coverage   92.50%   92.50%             
=========================================
  Files         484      484             
  Lines       34748    34748             
  Branches     2143     3236   +1093     
=========================================
  Hits        32145    32145             
  Misses       2603     2603             

Flag	Coverage Δ
app	92.50% <ø> (ø)
server	97.36% <ø> (ø)

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[lobehubbot]

❤️ Great PR @SpeedupMaster ❤️

The growth of project is inseparable from user feedback and contribution, thanks for your contribution! If you are interesting with the lobehub developer community, please join our discord and then dm @arvinxx or @canisminor1990. They will invite you to our private developer channel. We are talking about the lobe-chat development or sharing ai newsletter around the world.
项目的成长离不开用户反馈和贡献，感谢您的贡献! 如果您对 LobeHub 开发者社区感兴趣，请加入我们的 discord，然后私信 @arvinxx 或 @canisminor1990。他们会邀请您加入我们的私密开发者频道。我们将会讨论关于 Lobe Chat 的开发，分享和讨论全球范围内的 AI 消息。

[lobehubbot]

🎉 This PR is included in version 1.20.3 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀