Feat/refractor llm provider

[alcholiclg]

Change Summary

1. refractor llm provider: data-driven provider layer with 10 providers

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.
• Documentation reflects the changes where applicable

[gemini-code-assist]

Code Review

This pull request refactors the MS-Agent framework by introducing a knowledge-driven skill system (v2) integrated directly into the standard agent loop, a data-driven LLM provider layer with adaptive retry, a pluggable retriever framework, and a robust project/session management system. The code review identified several critical security and stability issues, including path traversal bypass vulnerabilities in path resolution, potential TypeError and ValueError crashes during streaming merges and string splitting, ZeroDivisionError risks in the BM25 retriever, and Windows compatibility issues with Path.rename().

Important

The consumer version of Gemini Code Assist on GitHub is being sunset. Starting June 18, 2026, new organization installations will be blocked, and all code review activity will officially cease on July 17, 2026.
For more details on the timeline and next steps, please review the Help Documentation.