Fix broken documentation links in README files

📝 Description

This PR fixes broken and incorrect documentation links in both English and Chinese README files.

🔧 Changes

README.md

• Fixed MiniMax API reference link from https://platform.minimaxi.com/document to https://platform.minimax.io/docs (correct global platform URL)

README_CN.md

• Fixed production guide link from docs/PRODUCTION_DEPLOYMENT_GUIDE_CN.md to docs/PRODUCTION_GUIDE_CN.md (correct filename)
• Fixed MiniMax API reference link from https://platform.minimaxi.com/document to https://platform.minimaxi.com/docs (correct path)

🎯 Impact

• Users following the documentation links will now reach the correct resources
• Improved documentation accuracy and user experience
• Ensures consistency between English and Chinese documentation

✅ Testing

• Verified all referenced files exist in the repository
• Confirmed URLs are accessible and correct

📋 Checklist

• Documentation links verified
• Both English and Chinese versions updated
• No breaking changes