- Fix MiniMax API base URL from api.minimax.chat to api.minimax.io
- Add MiniMax model presets (M2.7, M2.7-highspeed, M2.5, M2.5-highspeed)
with correct context window sizes (1M for M2.7, 204K for M2.5)
- Update MiniMax description to reflect latest M2.7/M2.5 model series
- Add MiniMax to README provider tables (Chinese + English)
- Add 12 unit tests for model presets validation
Co-authored-by: PR Bot <pr-bot@minimaxi.com>