Wheel packaging may exclude py.typed and .pyi stubs

[zeevdr]

Description

sdk/pyproject.toml:47 declares setuptools.packages.find but no [tool.setuptools.package-data]. py.typed and the generated .pyi stubs may not end up in the built wheel, contradicting the "Typing :: Typed" classifier.

Acceptance criteria

• Add [tool.setuptools.package-data] opendecree = ["py.typed", "_generated/**/*.pyi"]
• CI check: build the wheel and assert py.typed is present
• Document the typing guarantee in README