Add Python type stubs for straleio SDK

[petterlindstrom79]

The straleio Python SDK works but doesn't ship with py.typed marker or inline type annotations for all public methods. Adding proper type hints improves the developer experience in VS Code and PyCharm.

What to do:

• Add py.typed marker file to packages/sdk-python/straleio/
• Add type annotations to the main Strale class methods (do(), suggest(), etc.)
• Verify with mypy --strict on the package

Good first issue — no logic changes, just type annotations.