feat: add CrewAI APort task verification decorator (#30)

[lout33]

Summary

Closes #30 by adding a CrewAI-focused APort verification decorator under examples/agent-frameworks/crewai.

The integration includes:

• @aport_verify decorator for sync and async task functions
• A small dependency-free APortHTTPClient fallback
• Support for static, callable, kwarg, or environment-derived agent IDs
• Context builders for passing task-specific facts into APort verification
• Clear APortVerificationError handling before task execution
• A runnable example and README usage docs
• Unit tests covering successful verification, deny responses, derived agent IDs, env agent IDs, strict/non-strict behavior, and async tasks

Files

• examples/agent-frameworks/crewai/src/aport_verify.py — core decorator and client
• examples/agent-frameworks/crewai/src/__init__.py — module init
• examples/agent-frameworks/crewai/README.md — full documentation
• examples/agent-frameworks/crewai/tests/test_aport_verify.py — 12 unit tests
• examples/agent-frameworks/crewai/examples/basic_usage.py — runnable demo

Validation

PYTHONPATH=src python3 -m unittest discover -s tests  # 12 tests pass
python3 -m compileall src tests examples            # syntax OK
PYTHONPATH=src python3 examples/basic_usage.py      # demo runs

Bounty

This PR closes #30 which has a $10 USD Hacktoberfest bounty.

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Bounty: $10 USD