Add Astral's ty type checker (written in Rust, 10-100x faster than mypy)
as a second type checking layer. Both run in pre-commit and CI.
Fixed type issues caught by ty:
- config.py: explicit Host constructor to avoid dict unpacking issues
- executor.py: wrap subprocess.run in closure for asyncio.to_thread
- api.py: use getattr for Jinja TemplateModule macro access
- test files: fix playwright driver_path tuple handling, pytest rootpath typing
- Tests for config module (Host, Config, load_config)
- Tests for ssh module (local detection, command execution)
- 30 tests, all passing
- pytest-asyncio for async test support
- ruff check + format with ALL rules (ignoring D, ANN, FBT, T201)
- mypy strict mode with pydantic plugin
- Standard pre-commit hooks (trailing whitespace, end-of-file, etc.)
- Fix all type annotations for strict mypy compliance
