fix: Add pytest-asyncio to requirements.txt for CI

The CI workflow uses requirements.txt for dependencies, so pytest-asyncio
must be added there as well as pyproject.toml.

This fixes the ModuleNotFoundError for mcp.types by ensuring all test
dependencies are installed in the CI environment.

requirements.txt

@@ -26,6 +26,7 @@ PyMuPDF==1.24.14
 Pillow==11.0.0
 pytesseract==0.3.13
 pytest==8.4.2
+pytest-asyncio==0.24.0
 pytest-cov==7.0.0
 python-dotenv==1.1.1
 python-multipart==0.0.20