chore(main): release 1.47.0

[release-please]

🤖 I have created a release beep boop

1.47.0 (2025-10-24)

Features

• Support default global location when not using api key with vertexai backend (6340ce0)

Bug Fixes

• Check environment Vertex AI api key for credential precedence (9bd758c)
• Setting custom httpx async client will ensure using httpx client even if aiohttp is installed (7bd1bde)
• Support custom_base_url for Live and other APIs when project/location are unset and even when project/location are set in the environment, and avoid Automatic Default Credentials (7bd1bde)

Documentation

• Add docstring for classes and fields that are not supported in Gemini or Vertex API (4a6c6af)
• Add docstring for enum classes that are not supported in Gemini or Vertex API (909f26b)
• Update Codegen Instructions to include newer models and use consistent formatting. (f0b0a94)

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