smolagents: simple agent framework with CodeAgent and HfApiModel support

AI Impact Summary

smolagents provides a lightweight, code-first framework for building agents that perform actions by calling external tools, using CodeAgent with tools like DuckDuckGoSearchTool and HfApiModel. It supports sandboxed execution via E2B and Hub-based sharing of tools, plus broad LLM compatibility through HfApiModel and LiteLLM. The change shifts teams toward dynamic, code-driven agent workflows instead of fixed pipelines, with security and governance considerations around tool execution and external calls. It also marks transformers.agents as a predecessor to be replaced in the future, affecting migration planning for existing users.