feat: add CrewAI APort verification decorator

[mawxcodehub]

Summary

• Adds an @aport_verify decorator for CrewAI-style task callables.
• Verifies with APort before task execution and raises APortVerificationError on deny/failure.
• Includes examples for refund approval, data export, and repository merge task types.
• Adds tests for allow, deny-before-execution, async tasks, dynamic context, and serialization.

Verification

• python -m compileall src examples tests
• PYTHONPATH=src python -m pytest -q

Closes #3.