build: type-check with ty in a pre-commit hook

ty joins the dev dependency group, locked at 0.0.89, and a local
hook runs `uv run ty check` over the whole project whenever Python
files change. [tool.ty.src] limits the check to pqcli/ and tests/,
so agent worktrees under .claude/ are not checked as duplicate
copies of the project.

pyproject.toml

@@ -40,7 +40,12 @@ requires = ["hatchling"]
 build-backend = "hatchling.build"
 
 [dependency-groups]
-dev = ["prek>=0.2", "pytest>=8.0"]
+dev = ["prek>=0.2", "pytest>=8.0", "ty>=0.0.89"]
+
+[tool.ty.src]
+# Only the package and its tests; agent worktrees under .claude/ would
+# otherwise be checked as duplicate copies of the project.
+include = ["pqcli", "tests"]
 
 [tool.ruff]
 line-length = 79