v0.6.1

What's Changed

• Re-export AgentRecognitionProofV1 from the top-level paybond_kit module so protocol recognition-proof inputs are available from the documented package entry point.
• Bump paybond-kit and the bundled native crate metadata to 0.6.1.

Why

This patch aligns the Python package entry point with the SDK reference and the existing protocol client surface.

Verification

• Focused SDK/protocol/A2A/MCP pytest set.
• scripts/verify_release.py using the working Python 3.13 release environment.

Note: twine check was skipped by the local verifier because twine is not installed; wheel/sdist metadata inspection and smoke install passed.