Replace Azure Inference URL with GitHub AI URL

[Copilot]

This PR updates all references to the deprecated Azure inference endpoint with the new GitHub AI endpoint across the entire codebase.

Changes Made

• Replaced https://models.inference.ai.azure.com with https://models.github.ai in 56 Python files
• Updated URL references in multiple contexts:
  • OpenAI client instantiations (openai.OpenAI and openai.AsyncOpenAI)
  • LangChain configurations (openai_api_base parameter)
  • LlamaIndex configurations (api_base parameter)
  • PydanticAI configurations (base_url parameter)

Files Updated

All Python files in both the root directory and spanish/ subdirectory that contained the old Azure inference URL, including:

• Chat examples (chat.py, chat_async.py, chat_stream.py, etc.)
• Function calling examples (function_calling_*.py)
• RAG examples (rag_*.py, retrieval_augmented_generation.py)
• Structured outputs examples (structured_outputs_*.py)
• Library integration examples (chat_langchain.py, chat_llamaindex.py, chat_pydanticai.py)

Why This Change Is Needed

• The Azure inference endpoint https://models.inference.ai.azure.com is being deprecated
• GitHub AI endpoint https://models.github.ai provides better performance and reliability
• Ensures future compatibility for all GitHub-hosted projects
• Maintains consistency across the GitHub ecosystem

Verification

• ✅ All 56 instances successfully replaced
• ✅ No old URLs remain in the codebase
• ✅ Code formatting and linting standards maintained (ruff and black pass)
• ✅ All changes are minimal and surgical - only URL strings were modified

Fixes #29.

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[pamelafox]

@copilot For the else block for "github", where you changed the URL, please also change the MODEL_NAME to

MODEL_NAME = os.getenv("GITHUB_MODEL", "openai/gpt-4o")

The difference is now that the string is "openai/gpt-4o" instead of just "gpt-4o".

[Copilot]

@copilot For the else block for "github", where you changed the URL, please also change the MODEL_NAME to

MODEL_NAME = os.getenv("GITHUB_MODEL", "openai/gpt-4o")

...

Updated MODEL_NAME default for GitHub from "gpt-4o" to "openai/gpt-4o" in all 56 files. Fixed in commit 3b52120.