Add MiniMax as alternative LLM provider in research agent notebook

[octo-patch]

Summary

The research_ai_agent.ipynb notebook was hardcoded to use OpenAI (GPT-4). This PR adds MiniMax as a drop-in alternative provider, switchable via an environment variable.

MiniMax exposes an OpenAI-compatible REST API, so no extra dependencies are needed — the existing openai SDK works with just a different base_url and API key.

Changes

• docs/assets/use_cases/research_agent/research_ai_agent.ipynb
  • Replace hardcoded OpenAI-only setup with a two-provider config block (PROVIDER = os.environ.get("LLM_PROVIDER", "openai"))
  • Safe secret retrieval that works in both Google Colab and local environments
  • Default model for MiniMax: MiniMax-M2.7 with a 204K-token context window
  • Update the setup markdown cell with a provider comparison table

Usage

OpenAI (default — no change needed):

OPENAI_API_KEY=sk-...  # as before

MiniMax:

LLM_PROVIDER=minimax
MINIMAX_API_KEY=your-key   # from https://www.minimaxi.com/

In Colab, add the relevant key via Tools → Secrets and set LLM_PROVIDER in an early cell or as an environment variable.

Why MiniMax?

• OpenAI-compatible API — zero extra dependencies
• MiniMax-M2.7 has a 204K-token context window, useful when ingesting large research paper corpora
• Provides an alternative for users in regions or organizations where OpenAI access is restricted