[NA] [DOCS] docs: document MiniMax regional endpoints

[octo-patch]

Reason: Document the current MiniMax OpenAI-compatible and Anthropic-compatible base URLs for global and China accounts.

Details

Adds a MiniMax integration guide to the current documentation site. The guide covers both supported SDK protocols, lists the regional base URLs, and uses the current MiniMax text model identifiers.

• Add the MiniMax guide to the current Fern navigation.
• Add MiniMax to the model provider integration overview.
• Keep generated model and pricing files unchanged.

Change checklist

• User facing
• Documentation update

Issues

• N/A

AI-WATERMARK

AI-WATERMARK: yes

• If yes:
  • Tools: Codex
  • Model(s): Codex runtime model
  • Scope: Documentation research, implementation, and validation
  • Human verification: Reviewed repository conventions, related pull requests, the final diff, and local Fern output

Testing

• npm ci
• git diff --check
• Parsed fern/versions/latest.yml and verified the MiniMax navigation entry resolves to the new page.
• Verified the documented model identifiers and regional endpoints against the configured target facts.
• npx fern docs dev --port 3017 did not become ready locally and was stopped; no preview result is claimed.
• npx fern docs broken-links --strict completed but reported 159 pre-existing broken links outside the new MiniMax page. The new page was not reported.

Documentation

Adds the current MiniMax integration page and links it from the current navigation and integration overview.

[jverre]

Thanks @octo-patch for the PR, merged :)