docs: add MLflow AI Gateway as LLM provider

[PattaraS]

Summary

Adds an MLflow AI Gateway Accordion entry to docs/en/concepts/llms.mdx, showing how to use it as an OpenAI-compatible LLM backend in CrewAI.

English only — translations for ar, ko, and pt-BR are welcome as a follow-up.

Note: This PR should be labeled llm-generated per the contributing guide — we cannot add labels from a fork.

What is MLflow AI Gateway?

MLflow AI Gateway is a database-backed LLM proxy built into the MLflow tracking server (MLflow ≥ 3.0). It provides a unified OpenAI-compatible API across dozens of providers with encrypted secrets management, fallback/retry, traffic splitting, and per-endpoint token budgets.

Changes

• Single Accordion section added to docs/en/concepts/llms.mdx with:
  • Brief description of MLflow AI Gateway
  • Setup instructions (start MLflow server, create endpoint in UI)
  • Code example using LLM(model="openai/<endpoint-name>", base_url="...")
  • Note about LiteLLM dependency

AI Disclosure

This pull request was AI-assisted by Claude. All content was reviewed and validated by a human contributor.

[PattaraS]

@greysonlalonde Would you mind taking a look? Thanks!

[PattaraS]

Hi @lorenzejay, friendly ping on this PR. We're from the MLflow team and working on adding MLflow AI Gateway integration guides across major agent frameworks. MLflow AI Gateway (MLflow >= 3.0) is an open-source LLM proxy with built-in secrets management, fallback/retry, traffic splitting, and usage tracing. This PR adds a small Accordion section to the LLMs page showing how to use it with CrewAI via base_url (English only, happy to add translations as follow-up). Thanks!