* Use anyio as testing backend
* Remove asyncio markers
* Update streamable http tests
* Replace all subprocess tests
* Replace anyio task groups with asyncio context managers in tests
- Convert run_server_async from anyio task group pattern to asyncio.create_task with async context manager
- Remove task_group fixture from conftest
- Update all test fixtures to use async with run_server_async pattern
- Remove TaskGroup imports from all test files
- Tests now work with pytest-asyncio instead of pytest-anyio
* Update test_github_provider_integration.py
Exposes MCP session ID from HTTP headers to enable Redis-based data sharing
between tools. Returns None for stdio/memory transports as expected.
Fixes#875, addresses python-sdk#986, python-sdk#942, python-sdk#485
🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>