feat: add and expand MiniMax provider support

[Hi-Jiajun]

Summary

This PR adds and expands MiniMax support across OpenMAIC's built-in providers, including LLM, TTS, image, and video.

What changed

• LLM
  • keep MiniMax on the Anthropic-compatible provider type
  • update the default MiniMax base URL to https://api.minimaxi.com
  • add MiniMax-M2, MiniMax-M2.1, MiniMax-M2.1-lightning, MiniMax-M2.1-highspeed, MiniMax-M2.5, MiniMax-M2.5-lightning, MiniMax-M2.5-highspeed, and MiniMax-M2.7-highspeed
• TTS
  • add built-in MiniMax TTS model options: speech-2.8-turbo, speech-2.8-hd, speech-2.6-turbo, speech-2.6-hd, speech-02-turbo, speech-02-hd
  • persist the selected TTS model in settings
  • expose the MiniMax TTS model selector in the settings UI
  • pass ttsModel through /api/generate/tts
  • align default MiniMax TTS base URL with https://api.minimaxi.com
• Image
  • add the built-in minimax-image provider integration
  • add image-01 and image-01-live
  • align the default MiniMax image base URL with https://api.minimaxi.com
• Video
  • add the built-in minimax-video provider integration
  • add MiniMax-Hailuo-2.3, MiniMax-Hailuo-2.3-Fast, MiniMax-Hailuo-02, T2V-01-Director, and T2V-01
  • align the default MiniMax video base URL with https://api.minimaxi.com
• Docs/config
  • refresh .env.example, README.md, and README-zh.md with MiniMax examples and updated defaults

Validation

• pnpm eslint lib/ai/providers.ts
• pnpm eslint lib/audio/constants.ts lib/media/image-providers.ts lib/media/video-providers.ts lib/ai/providers.ts
• pnpm eslint components/settings/audio-settings.tsx app/api/generate/tts/route.ts lib/store/settings.ts lib/audio/constants.ts lib/audio/tts-providers.ts
• pnpm build

Notes

• This PR does not add MiniMax Music support.
• The implementation in this PR was written 100% by GPT-5.4.

[Hi-Jiajun]

Synced this branch with the latest upstream/main on 2026-03-23 and resolved the provider/config merge conflicts locally.

This keeps the MiniMax image, video, and TTS changes aligned with the then-current main branch, including the newer Grok and ElevenLabs provider additions, so the PR is easier to review against a current baseline.

[Hi-Jiajun]

Synced this branch again with the latest upstream/main on 2026-03-24 and resolved the new merge conflict introduced by the Discussion TTS changes.

The branch returned to a mergeable state after that sync, and the refreshed Lint & Typecheck run passed.

[wyuc]

Three issues:

1. LLM defaultBaseUrl dropped the /anthropic/v1 suffix. Since MiniMax uses type: 'anthropic', this will break all LLM calls.

2. Base URLs are inconsistent across .env.example, README EN, README ZH, and adapter code (mixing api.minimaxi.com, api.minimax.com, api.minimax.io). Please unify per service.

3. Please verify the video adapter's file download path. The code constructs /v1/files/${file_id} as the URL directly. Check if MiniMax requires a separate file retrieval call instead.

Also consider adding MiniMax-M2.7 (non-highspeed) from PR #170 since this PR is the more comprehensive MiniMax addition.

[Hi-Jiajun]

Addressed the latest review feedback in commit 96dd9f2:

• Fixed MiniMax LLM defaultBaseUrl to use the Anthropic-compatible https://api.minimaxi.com/anthropic/v1 endpoint, and added normalization so custom MiniMax base URLs also resolve correctly.
• Unified MiniMax examples and runtime defaults to the domestic https://api.minimaxi.com domain across .env.example, both READMEs, and adapters.
• Changed the MiniMax video adapter to call GET /v1/files/retrieve?file_id=... and use the returned download_url instead of constructing the file URL directly.
• Added MiniMax-M2.7 to the built-in MiniMax model list.

Also added a small Vitest check for the MiniMax provider defaults. Local eslint, tsc --noEmit, and vitest runs all pass.

[Hi-Jiajun]

Follow-up adjustment in commit 4b597a2:

• Restored MiniMax-Hailuo-2.3-Fast in the MiniMax video model list after re-checking the official MiniMax docs.

I initially removed it while narrowing the list, but the official MiniMax video/model documentation does list it, so the PR now keeps the video model list aligned with MiniMax's published availability.