Fix pylint for bink 0.7.1

[bladecoder]

What changed

• Format the Python bindings and add API docstrings so pylint passes.
• Replace implicit ctypes defaults and internal-pointer access with explicit wrapper APIs.
• Add AGENTS.md requiring pylint and the full test suite before any code change is considered complete or released.
• Bump the package version to 0.7.1.

Validation

• pylint $(git ls-files 'bink/*.py') — 10.00/10
• python -m unittest discover -v — 8 tests passed