- Upgrade grpcio from 1.59.0 to 1.60.0+ to support Python 3.14
- Upgrade grpcio-tools from 1.59.0 to 1.60.0+
- Ensure CI uses Python 3.11 via workflow configuration
- Remove .python-version file to avoid version conflicts
- Update pdm.lock with new dependency versions

This fixes CI failures caused by grpcio 1.59.0 not supporting Python 3.14.

- Change [dependency-groups] to [tool.pdm.dev-dependencies] for PDM 2.10 compatibility
- Update workflow to use 'pdm install -d' instead of '-G dev'
- Fix pool.py to add missing do_ping parameter in execute() method
- Regenerate pdm.lock with new configuration

This resolves CI errors caused by PDM version mismatch and missing do_ping parameter.