feat(images): add MiniMax image generation

[octo-patch]

Reason: Enable MiniMax image generation in the existing generate_image_asset pipeline.

• Add the image-01 adapter with global and China endpoints, Bearer authentication, aspect-ratio or size mapping, and validated base64 image results.
• Add MiniMax image settings with regional selection and separate custom credentials; keep inherited text endpoints out of image requests.
• Cover regional requests, image decoding, API errors, settings persistence, and tool option forwarding.

Validation:

• corepack pnpm --filter @open-codesign/providers exec vitest run src/images.test.ts
• corepack pnpm --filter @open-codesign/desktop exec vitest run src/main/image-generation-settings.test.ts
• corepack pnpm lint
• corepack pnpm typecheck
• CI=1 corepack pnpm test
• corepack pnpm --filter @open-codesign/desktop exec electron-vite build
• git diff --check

API behavior is covered with mocked responses; no paid image generation request was made.

[github-actions]

Review mode: initial

Findings

• [Minor] outputFormat is ignored for MiniMax but its control stays enabled — apps/desktop/src/renderer/src/components/settings/ImageGenerationTab.tsx:251 disables only the quality select for provider === 'minimax', while generateMiniMaxImage (packages/providers/src/images.ts:118) never reads options.outputFormat; the new test even passes outputFormat: 'webp' and still expects mimeType: 'image/png'. A user can therefore select a format that silently has no effect.
  Suggested fix: disable the Output format control when settings.provider === 'minimax' (same treatment as quality), or label that MiniMax controls the returned encoding.

• [Minor] Switching away from MiniMax leaves credentialMode stuck at custom — apps/desktop/src/main/image-generation-settings.ts:367 forces custom only when moving to minimax and never restores the previous mode. The renderer then re-sends settings.credentialMode (now custom) for the next provider, so a user who previously relied on an inherited OpenAI/OpenRouter image key ends up in custom mode after a minimax round-trip.
  Suggested fix: restore the prior mode when leaving minimax, e.g. providerChanged && provider === 'minimax' ? 'custom' : providerChanged ? 'inherit' : current.credentialMode.

Questions

• Does the MiniMax image_generation endpoint accept width/height? generateMiniMaxImage sends width/height (derived from size) whenever aspectRatio is absent, but only mocked responses were exercised ("no paid image generation request was made"). If MiniMax only accepts aspect_ratio, the size path is effectively dead — worth confirming the real request/response shape once.
• Is the custom image key stored once per install or per provider? The settings view exposes a single hasCustomKey/maskedKey; if it is shared, a MiniMax custom key may be reused for OpenAI/OpenRouter requests after the switch above.

Summary

• Review mode: initial
• The MiniMax adapter (packages/providers/src/images.ts), regional base URLs and Bearer auth (packages/shared/src/config.ts), response/error validation, and the endpoint isolation from inherited text config look consistent with the existing OpenAI/OpenRouter adapters. Added Vitest cases cover the mocked paths, a changeset is present, and no new dependencies or direct SDK imports are introduced.
• No blockers found. Residual risks are the unverified live request/response shape (especially width/height) and the credential-mode stickiness noted above.

Testing

• Not run (automation). Suggested follow-ups: a Vitest case asserting outputFormat/quality are ignored for minimax at the option/UI layer, and one live (or recorded-fixture) MiniMax request to confirm width/height vs aspect_ratio.

Open-CoDesign Bot