feat: add MiniMax AI as LLM provider example

[octo-patch]

Summary

• Add MiniMax M2.7 as an alternative LLM provider for Bindu agents via OpenAI-compatible API (agno OpenAILike)
• New example agent: examples/beginner/minimax_example.py with research assistant capabilities
• Update .env.example, README.md, and examples/README.md with MiniMax documentation
• 24 unit tests + 3 integration tests validating configuration, file structure, and API connectivity

Why MiniMax?

MiniMax AI offers high-performance LLM models:

• MiniMax-M2.7: 1M context window, strong reasoning
• MiniMax-M2.7-highspeed: Faster variant
• MiniMax-M2.5: 204K context, cost-effective
• MiniMax-M2.5-highspeed: Fastest option

All models are accessible via OpenAI-compatible API, making integration seamless with agno's OpenAILike class.

Changes (5 files, 330 additions)

File	Description
examples/beginner/minimax_example.py	New MiniMax research agent example
examples/beginner/.env.example	Added MINIMAX_API_KEY configuration
README.md	Added MiniMax to prerequisites and LLM providers list
examples/README.md	Added MiniMax example to examples listing
tests/unit/test_minimax_example.py	24 unit + 3 integration tests

Test plan

• 24 unit tests pass (file structure, AST validation, config, README updates)
• 3 integration tests pass (API connectivity, M2.7 chat, M2.7-highspeed chat)
• Verify example runs with python examples/beginner/minimax_example.py