[Lobe i18n] Improve Usage section for better onboarding experience

[shinshin86]

💻 变更类型 | Change Type

• ✨ feat
• 🐛 fix
• ♻️ refactor
• 💄 style
• 🔨 chore
• 📝 docs

🔀 变更说明 | Description of Change

Background:
When I first tried using Lobe i18n, I encountered some confusion in the Usage section of the README.
Specifically, the need to create a configuration file (e.g., .i18nrc.js) before running commands like lobe-i18n wasn’t immediately clear.

Proposal:
This PR updates the Usage section to include:

1. A step-by-step guide for initializing the configuration.
2. An example of a .i18nrc.js configuration file.

Goal:
By making the setup process clearer, especially for first-time users, this PR aims to improve the onboarding experience.

---

Request for Review
I hope this change can contribute to enhancing the usability of Lobe i18n. Please let me know if there are any adjustments or improvements needed.

Thank you for your time and consideration!

📝 补充信息 | Additional Information

[lobehubbot]

👍 @shinshin86

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。

[lobehubbot]

❤️ Great PR @shinshin86 ❤️

The growth of project is inseparable from user feedback and contribution, thanks for your contribution!
项目的成长离不开用户反馈和贡献，感谢您的贡献!

[lobehubbot]

🎉 This PR is included in version 1.20.2 🎉

The release is available on npm package (@latest dist-tag)

Your semantic-release bot 📦🚀

[lobehubbot]

🎉 This PR is included in version 1.10.1 🎉

The release is available on npm package (@latest dist-tag)

Your semantic-release bot 📦🚀

[lobehubbot]

🎉 This PR is included in version 2.15.3 🎉

The release is available on npm package (@latest dist-tag)

Your semantic-release bot 📦🚀

[lobehubbot]

🎉 This PR is included in version 1.3.2 🎉

The release is available on npm package (@latest dist-tag)

Your semantic-release bot 📦🚀

[lobehubbot]

🎉 This PR is included in version 1.4.3 🎉

The release is available on npm package (@latest dist-tag)

Your semantic-release bot 📦🚀