Add MiniMax M3 installer option

[octo-patch]

Reason: add target provider/model to existing provider registry

Summary

• Add MiniMax-M3 as the default MiniMax installer model option.
• Update generated MiniMax provider config to use the /anthropic endpoints for global and CN regions.
• Include MiniMax-M3 metadata with 1M context and current pricing/cache-read settings.

Test plan

• bash -n config-menu.sh
• bash -n install.sh
• bash -n docker-entrypoint.sh
• bash -n scripts/preflight-check.sh

🤖 Generated with Claude Code

[octo-patch]

This pull request has been replaced by #41, rebuilt from the latest main with a clean commit history and complete model and protocol coverage.