fix: add py.typed marker for PEP 561 support

.github/workflows/test.yaml

@@ -46,10 +46,16 @@ jobs:
       - run: pip install build twine
       - run: python -m build
       - run: twine check dist/*
+      - name: Wheel ships py.typed (PEP 561)
+        run: unzip -l dist/*.whl | grep -F 'h5i/py.typed'
       - name: Wheel installs and imports
         run: |
           pip install dist/*.whl
           python -c "import h5i.orchestra as o; print(o.__version__)"
+      - name: Installed wheel is typed (mypy smoke)
+        run: |
+          pip install mypy
+          python -m mypy -c "from h5i.orchestra import Conductor; reveal_type(Conductor)"
 
   # Build the Rust engine from the sibling h5i repo and run the cross-process
   # integration suite against the real `h5i orchestra serve` binary. The

pyproject.toml

@@ -32,7 +32,7 @@ Repository = "https://github.com/h5i-dev/h5i-python"
 Issues = "https://github.com/h5i-dev/h5i-python/issues"
 
 [project.optional-dependencies]
-dev = ["pytest>=8", "pytest-asyncio>=0.23", "ruff>=0.6"]
+dev = ["pytest>=8", "pytest-asyncio>=0.23", "ruff>=0.6", "mypy>=1.8"]
 
 [tool.hatch.build.targets.wheel]
 packages = ["src/h5i"]