Found docs updates needed from ADK python release v1.14.0 to v1.14.1

[adk-bot]

I have analyzed the changes between ADK Python releases v1.14.0 and v1.14.1.
Here are the recommended updates for the ADK documentation:

1. New Spanner similarity_search tool.
   A new tool similarity_search has been added to the Spanner toolset. The documentation should be updated to include this new tool.

   Proposed Change:
   In docs/tools/built-in-tools.md, add a new section for the Spanner toolset, similar to the BigQuery section, and document the similarity_search tool.

   Reasoning:
   This is a major new feature that needs to be documented for users to be able to use it.

   Reference:

   • google/adk-python@0c1f1fa
   • src/google/adk/tools/spanner/search_tool.py
   • src/google/adk/tools/spanner/spanner_toolset.py

2. Update Gemini Model to gemini-2.5-flash.
   The default Gemini model has been updated from gemini-2.0-flash to gemini-2.5-flash. All occurrences of gemini-2.0-flash and gemini-1.5-flash in the documentation should be updated.

   Proposed Change:
   Replace all instances of gemini-2.0-flash and gemini-1.5-flash with gemini-2.5-flash in the following files:

   • docs/a2a/quickstart-consuming.md
   • docs/a2a/quickstart-exposing.md
   • docs/agents/config.md
   • docs/agents/custom-agents.md
   • docs/agents/llm-agents.md
   • docs/agents/models.md
   • docs/agents/multi-agents.md
   • docs/artifacts/index.md
   • docs/deploy/gke.md
   • docs/get-started/quickstart.md
   • docs/get-started/streaming/quickstart-streaming-java.md
   • docs/get-started/streaming/quickstart-streaming.md
   • docs/observability/arize-ax.md
   • docs/observability/logging.md
   • docs/observability/phoenix.md
   • docs/observability/weave.md
   • docs/plugins/index.md
   • docs/safety/index.md
   • docs/sessions/memory.md
   • docs/sessions/state.md
   • docs/streaming/custom-streaming-ws.md
   • docs/streaming/custom-streaming.md
   • docs/streaming/streaming-tools.md
   • docs/tools/built-in-tools.md
   • docs/tools/google-cloud-tools.md
   • docs/tools/mcp-tools.md
   • docs/tools/openapi-tools.md
   • docs/tools/third-party-tools.md
   • docs/tutorials/agent-team.md

   Reasoning:
   To ensure the documentation is up-to-date with the latest recommended model.

   Reference:

   • google/adk-python@0c1f1fa
   • src/google/adk/models/google_llm.py

3. New save_live_audio flag in RunConfig.
   A new flag save_live_audio has been added to RunConfig to save live audio data.

   Proposed Change:
   In docs/runtime/runconfig.md, add a new row to the parameters table for the save_live_audio flag.

   Reasoning:
   To document the new feature for live agents.

   Reference:

   • google/adk-python@0c1f1fa
   • src/google/adk/agents/run_config.py

4. BigQuery Tool location parameter.
   The BigQuery toolset now supports a location parameter.

   Proposed Change:
   In docs/tools/built-in-tools.md, update the BigQuery toolset description to include the new location parameter.

   Reasoning:
   To document the new feature for the BigQuery toolset.

   Reference:

   • google/adk-python@0c1f1fa
   • src/google/adk/tools/bigquery/client.py
   • src/google/adk/tools/bigquery/config.py
   • src/google/adk/tools/bigquery/metadata_tool.py
   • src/google/adk/tools/bigquery/query_tool.py

5. New adk_documentation and live_agent_api_server_example samples.
   Two new samples, adk_documentation and live_agent_api_server_example, have been added to the adk-python repository.

   Proposed Change:
   In docs/get-started/index.md, add a note about the new samples available in the adk-python repository, with links to the samples.

   Reasoning:
   To make users aware of the new samples.

   Reference:

   • google/adk-python@0c1f1fa
   • contributing/samples/adk_documentation/
   • contributing/samples/live_agent_api_server_example/