Merge https://github.com/google/adk-python/pull/6458
Live/audio agent eval was only exercisable through private internal service imports; the public surface (CLI, dev-server, AgentEvaluator) always ran non-live text inference, so users had no supported path to evaluate Live API agents with a simulated audio user.
This threads `use_live` through all three public entrypoints, fixes the live-send path so native-audio models accept simulated user audio, and lets the dev-server select an audio (`llm_audio`) user simulator over HTTP. Live transcriptions are consolidated to text, with the text response preferred as the gradable output for turns carrying both audio and a transcript.
Adds a runnable sample (`live_non_blocking_tool_agent` evalset + `test_config` with `use_live: true` and a Gemini TTS audio simulator) plus unit tests covering `use_live` propagation, request validation, resampling, and the realtime-audio send path.
COPYBARA_INTEGRATE_REVIEW=https://github.com/google/adk-python/pull/6458 from allen-stephen:feat/live-eval-parity 3fc33a2616d1515c822387deb8d70c27d5bc6244
PiperOrigin-RevId: 954725627
Stephen Allen
5091f0a65a