Anthropic cleanup

[evanmschultz]

Anthropic client cleanup

• Renamed TestLLMClient to MockLLMClient to eliminate pytest warning
• Moved Anthropic integration tests to llm_client directory
• Added ANTHROPIC_API_KEY to .env.example
• Removed temporary debug logging from AnthropicClient

I have read the CLA Document and I hereby sign the CLA

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[!IMPORTANT] Cleaned up Anthropic client integration by renaming classes, moving tests, adding ANTHROPIC_API_KEY, and removing debug logs.

• Behavior:
  • Removed temporary debug logging from AnthropicClient in anthropic_client.py.
• Environment:
  • Added ANTHROPIC_API_KEY to .env.example.
• Testing:
  • Renamed TestLLMClient to MockLLMClient in test_client.py to eliminate pytest warning.
  • Moved test_anthropic_client_int.py from tests/integrations to tests/llm_client.

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