add mcp-playground by ms_agent

[mushenL]

Change Summary

Related issue number

Checklist

• [ ] The pull request title is a good summary of the changes - it will be used in the changelog
• [ ] Unit tests for the changes exist
• [ ] Run pre-commit install and pre-commit run --all-files before git commit, and passed lint check.
• [ ] Some cases need DASHSCOPE_TOKEN_API to pass the Unit Tests, I have at least pass the Unit tests on local
• [ ] Documentation reflects the changes where applicable
• [ ] My PR is ready to review, please add a comment including the phrase "please review" to assign reviewers