docs: add the Databricks Agents page for the agent gateway

[mateo-berri]

TLDR

Adds docs/a2a_databricks_agent.md, the page for registering a Databricks ResponsesAgent (Model Serving or a Databricks App) as a LiteLLM agent and calling it through /a2a/<agent> or model: a2a/<agent>, with the endpoint URL shapes, the credential order, the OAuth M2M and environment service principal setups, the request parameters, and a sidebar entry under the A2A section. Pairs with BerriAI/litellm#45681

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Note

Low Risk
Documentation and sidebar navigation only; no runtime or security behavior changes in this PR.

Overview
Adds Databricks Agents documentation for the Agent Gateway: a new page that explains registering a Databricks ResponsesAgent (databricks_agent) for Model Serving or Databricks Apps, and invoking it via /a2a/<agent> or model: a2a/<agent> on chat, responses, and messages endpoints.

The page covers request/response mapping (chat → Responses API), api_base URL shapes, credential precedence (OAuth M2M, PAT, env vars, client Authorization), registration via UI / config.yaml / REST, streaming, passthrough params (custom_inputs, context, databricks_options), and unsupported message types / drop_params behavior. sidebars.js links the doc under Agent Gateway after Invoking A2A Agents.

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Project	Deployment	Actions	Updated
litellm	Ready	Preview	Oct 11, 2026 3:50pm UTC

[mateo-berri]

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