fix: correct SSE routing and portable MCP config

[jju666]

Summary

• Fix SSE message routing by mounting SseServerTransport.handle_post_message as an ASGI app, matching the MCP Python SDK example.
• Add a testable create_sse_app() and make python -m modsdk_mcp --sse start SSE mode correctly.
• Replace hard-coded local Windows paths in repo config/docs with portable <PROJECT_ROOT> or relative paths, and ignore Python cache files.
• Also remove the non-GBK startup log emoji so SSE mode can start in Windows redirected output environments.

This is a refreshed fix for the same root issue described in #4, based on the current upstream main instead of the stale PR branch.

Verification

• python -m unittest tests.test_sse_app
• python -m unittest discover
• Started python -m modsdk_mcp --sse on 127.0.0.1:8765 and verified GET /health returns {status:ok,server:netease-modsdk-mcp}.