feat: add Gemini 3.1 Flash Live support for run_live()

[imazizongit]

Summary

Adds support for gemini-3.1-flash-live-preview in ADK's bidi-streaming pipeline (run_live()). Without these changes, 3.1 models fail with WebSocket errors (1007/1008/1011).

Changes

Backward-compatible upgrades (all models)

1. send_realtime(): Use audio= instead of deprecated media= parameter in send_realtime_input(). The media= parameter produces the deprecated mediaChunks wire format which 3.1 rejects. The audio= parameter works on all models.

2. send_content(): Use send_tool_response() instead of session.send(LiveClientToolResponse(...)) for function responses. This is the current non-deprecated API.

3.1-specific changes (conditional on model_version)

3. send_content() text routing: 3.1 models reject LiveClientContent for mid-conversation text with error 1007: Request contains an invalid argument. Text content is routed through send_realtime_input(text=...) when model_version contains "3.1". Uses the existing self._model_version field.

4. connect() history_config: 3.1 models require HistoryConfig(initial_history_in_client_content=True) for session history. Injected in Gemini.connect() when model contains "3.1" and not already set by the caller.

Not included (model limitations, documented in #5075)

The following LiveConnectConfig fields are not supported by 3.1 models and will cause connection errors:

• enable_affective_dialog (1011 Internal error)
• context_window_compression (1007 Invalid argument)
• proactivity (1007 Unknown name)

These are model API limitations, not ADK bugs. Users should not set these fields when using 3.1 models.

Testing

• Tested in production with real PSTN phone calls via Telnyx
• Verified tool calling (collect_caller_data, end_conversation) works on 3.1
• Verified audio input/output works with native audio bidi-streaming
• Backward compatible: 2.5 models continue to work without changes

Related

• Fixes ADK does not support the newest gemini-3.1-flash-live-preview #5018
• See ADK run_live() incompatible with gemini-3.1-flash-live-preview (5 breaking issues) #5075 for full incompatibility documentation

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[adk-bot]

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[rohityan]

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[imazizongit]

Hi @imazizongit ,Thank you for your contribution! It appears you haven't yet signed the Contributor License Agreement (CLA). Please visit https://cla.developers.google.com/ to complete the signing process. Once the CLA is signed, we'll be able to proceed with the review of your PR. Thank you!

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