feat: add AG2 multi-agent framework integration

[faridun-ag2]

Summary

Add an integration for AG2 (formerly AutoGen), a multi-agent conversation
framework with 500K+ monthly PyPI downloads, 4,300+ GitHub stars, and 400+ contributors.

What's included

• AG2Agent — A Haystack @component that wraps AG2 multi-agent conversations
• Full serialization support (to_dict / from_dict)
• Configurable: model, system message, API type, code execution, auto-reply limits
• Unit tests with mocked dependencies
• README with standalone and pipeline usage examples

How it works

The AG2Agent component creates an AG2 AssistantAgent and UserProxyAgent,
runs a conversation with the input query, and returns the final reply along with
the full message history. It integrates seamlessly into Haystack pipelines.

Usage

from haystack import Pipeline
from haystack_integrations.components.agents.ag2 import AG2Agent

pipeline = Pipeline()
pipeline.add_component("agent", AG2Agent(model="gpt-4o-mini"))
result = pipeline.run({"agent": {"query": "Explain RAG."}})

Related

• AG2 framework: https://ag2.ai/
• AG2 GitHub: https://github.com/ag2ai/ag2
• AG2 PyPI: https://pypi.org/project/ag2/

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