feat: Auto-enable Google ADK integration in braintrust package

[AbhiPrasad]

This PR deprecates the braintrust-adk package in favour of using auto instrumentation with the braintrust package.

AI Summary

This branch moves the Google ADK integration from the standalone braintrust-adk PyPI package (integrations/adk-py/) into the main braintrust package, following the same pattern as Agno, Google GenAI, Claude Agent SDK, and other integrations.

What changed

New files in main package (py/):

• py/src/braintrust/wrappers/adk/__init__.py — ADK wrapper module with setup_adk, wrap_agent, wrap_runner, wrap_flow, wrap_mcp_tool
• py/src/braintrust/wrappers/adk/test_adk.py — Main integration tests (moved from integrations/adk-py/)
• py/src/braintrust/wrappers/adk/test_adk_mcp_tool.py — MCP tool tracing tests (moved from integrations/adk-py/)
• py/src/braintrust/wrappers/adk/test_auto_adk.py — Auto-instrument verification script
• py/examples/adk/ — Example scripts for auto and manual patching
• VCR cassettes moved to py/src/braintrust/wrappers/cassettes/

Modified files:

• py/src/braintrust/auto.py — Added adk: bool = True parameter to auto_instrument() and _instrument_adk() function
• py/noxfile.py — Added test_google_adk nox session with version matrix (latest, 1.14.1)
• py/Makefile — Added google-adk to install-optional

Integration package (integrations/adk-py/) — now a deprecation shim:

• src/braintrust_adk/__init__.py — Replaced with a thin shim that emits DeprecationWarning and re-exports only the public API from braintrust.wrappers.adk
• pyproject.toml — Bumped to 0.4.0, marked Development Status :: 7 - Inactive, requires braintrust>=0.6.0
• README.md — Added deprecation notice with migration instructions
• Tests replaced with test_reexports.py — verifies the public API re-exports and deprecation warning

Test fixes for cross-version compatibility

• Used ANY matcher for live_connect_config (structure differs between ADK versions)
• Changed output assertions from exact dict equality to individual key checks (newer ADK adds model_version)
• Added version-conditional check for avg_logprobs (only present in ADK >= 1.15.0)
• Fixed test_setup_adk_patches_mcp_tool — replaced fragile sys.modules manipulation with patch("google.adk.tools.mcp_tool.mcp_tool")

Migration Guide: braintrust-adk to braintrust

Before (old)

pip install braintrust-adk

from braintrust_adk import setup_adk

setup_adk(project_name="my-project")

After (new)

pip install braintrust
# No need for braintrust-adk anymore
pip uninstall braintrust-adk  # optional cleanup

Option 1: Auto-instrument (recommended)

from braintrust import auto_instrument

auto_instrument()
# ADK tracing is now enabled automatically alongside OpenAI, Anthropic, etc.

Option 2: Explicit setup

from braintrust.wrappers.adk import setup_adk

setup_adk(project_name="my-project")

What stays the same

• All public API functions (setup_adk, wrap_agent, wrap_runner, wrap_flow, wrap_mcp_tool) work identically
• Existing from braintrust_adk import setup_adk imports still work but emit a DeprecationWarning

What to update

1. Change imports from braintrust_adk to braintrust.wrappers.adk (or use auto_instrument())
2. Remove braintrust-adk from your dependencies — braintrust now includes ADK support with no extra package

[ibolmo]

LGTM, ty!

[ibolmo]

i wouldn't re-import private funcs