feat: add Azure AI Foundry support for Claude models

[satheeshKOLA532]

• Add AzureFoundryModels type definitions
• Implement with_azure_foundry() static method
• Support Azure endpoint authentication
• Addresses issue Issue: Add Azure AI Foundry support for Claude and Grok models #4071

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[satheeshKOLA532]

@theomonnom @longcw

The failing test test_chat_ctx.py::test_summarize appears to be unrelated to my changes.

My changes:

• Only modified Anthropic plugin files (llm.py and utils.py)
• All 71 other tests pass
• All code quality checks pass (ruff, mypy, type-check)

The failing test:

• Tests OpenAI chat context summarization
• Fails due to missing OpenAI API key in CI environment (HTTP 401 error)
• Error: "You didn't provide an API key"

This seems to be a pre-existing issue with the test suite configuration. Could you advise if:

1. This test should be skipped when API keys aren't available?
2. The CI should have mock API keys set up?
3. I should wait for this to be resolved separately?

Happy to make any adjustments needed for my Anthropic Azure AI Foundry changes.