feat: add ty type checker alongside mypy (#77)

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/test_cli_lifecycle.py

@@ -16,7 +16,9 @@ def _make_config(tmp_path: Path, services: dict[str, str] | None = None) -> Conf
     compose_dir = tmp_path / "compose"
     compose_dir.mkdir()
 
-    svc_dict = services or {"svc1": "host1", "svc2": "host2"}
+    svc_dict: dict[str, str | list[str]] = (
+        dict(services) if services else {"svc1": "host1", "svc2": "host2"}
+    )
     for svc in svc_dict:
         svc_dir = compose_dir / svc
         svc_dir.mkdir()

tests/web/test_htmx_browser.py

@@ -44,7 +44,9 @@ def _browser_available() -> bool:
     try:
         from playwright._impl._driver import compute_driver_executable
 
-        driver_path = compute_driver_executable()
+        driver_info = compute_driver_executable()
+        # compute_driver_executable returns (driver_path, browser_path) tuple
+        driver_path = driver_info[0] if isinstance(driver_info, tuple) else driver_info
         return Path(driver_path).exists()
     except Exception:
         return False
@@ -63,7 +65,7 @@ pytestmark = [
 @pytest.fixture(scope="session")
 def vendor_cache(request: pytest.FixtureRequest) -> Path:
     """Download CDN assets once and cache to disk for faster tests."""
-    cache_dir = Path(request.config.rootdir) / ".pytest_cache" / "vendor"
+    cache_dir = Path(request.config.rootpath) / ".pytest_cache" / "vendor"
     return ensure_vendor_cache(cache_dir)