Add MiniMax image generation provider (text-to-image and image-to-image)

[octo-patch]

Reason: Add the MiniMax image-generation provider (text-to-image and image-to-image) to the direct endpoint adapter layer.

Changes

• New lib/minimaxImageAdapter.ts calls POST /v1/image_generation with a Bearer API key.
  • Models: image-01 (text-to-image) and image-01-live (image-to-image).
  • Attached reference images are mapped to the subject_reference field (character subject, data URL).
  • --size is mapped to the closest supported aspect_ratio (1:1, 16:9, 4:3, 3:2, 2:3, 3:4, 9:16, 21:9); auto defers to the API default.
  • Both url and base64 response formats are parsed into a single base64 payload.
  • Region selects the global (https://api.minimax.io/v1) or China (https://api.minimaxi.com/v1) base URL.
  • base_resp.status_code is mapped to app error codes (auth, rate limit, balance, safety, bad request).
• lib/providerOptions.ts resolves the minimax provider and validates the model via normalizeMinimaxImageModel (added to lib/imageModels.ts). Web search, reasoning, and size controls are disabled.
• routes/models.ts exposes a minimax lane (image-01 / image-01-live, key-missing until configured).
• lib/capabilities.ts, lib/agentSettings.ts, and bin/lib/modelResolver.ts register minimax in their provider/lane lists.
• routes/keys.ts accepts MINIMAX_API_KEY (env or config) with status, validation, hot-update, and removal.
• lib/runtimeContext.ts and server.ts load and expose minimaxApiKey.
• config.ts/config.js add a minimaxProvider block (region, global/CN base URLs, default model, timeout).
• The classic, multimode, node, edit, and agent generation pipelines dispatch to generateViaMinimax, including the jpeg format group, image-to-image reference handling, and a 1-subject-reference cap (MINIMAX_REF_TOO_MANY) plus MINIMAX_MASK_UNSUPPORTED.
• routes/auth.ts redacts MINIMAX_API_KEY (and ATLASCLOUD_API_KEY) from the codex child env.
• CLI (gen/edit/multimode/node) and docs/CLI.md list the minimax lane.
• New tests/minimax-provider-contract.test.ts covers provider options, key-missing, text-to-image wire shape, subject_reference mapping, CN routing, ref cap, and safety/auth error mapping.
• Updated tests/models-endpoint-contract.test.ts, tests/cli-model-resolver.test.ts, tests/cli-capabilities-contract.test.js, tests/cli-feature-parity-contract.test.js, and the runtime test inventory for the new lane.

Checks

• tsc --noEmit -p tsconfig.json (server/lib/routes) — pass
• tsc --noEmit -p tsconfig.bin.json (bin) — pass
• node --test tests/minimax-provider-contract.test.ts — pass (9 tests)
• node --test for models-endpoint, cli-model-resolver, cli-feature-parity, cli-capabilities, atlascloud, gemini-api, image-model, generation-errors, reference-limits, generate route, agent-mode-llm-planner — pass
• node scripts/classify-tests.mjs --check (test inventory) — pass
• secret scan of the diff — clean

[lidge-jun]

Thanks for this — the MiniMax provider is now on dev via #120, with your commit 521ff85 cherry-picked so authorship is preserved.

I couldn't merge this branch as-is, so I fixed the blockers on top of your work rather than sending it back. What changed:

Key validation was billing the user. Sending {model, prompt} fills in the remaining fields from their defaults, so the probe was a real generation request — every key save or rotation produced an image that was then discarded. MiniMax exposes an OpenAI-compatible GET /v1/models, so validation now uses that, like every other provider here. The validation URL also follows the configured region now; it was pinned to the global host even for cn_zh.

Validation was fail-open. Only 401/1004/2049 were rejected, so a 403, 429, 500, or an unparseable body would store an invalid key. It now requires the documented list shape, and MiniMax reports errors inside 200 bodies so base_resp.status_code is checked too.

The model was being swapped silently. With a reference attached, a user's image-01 was sent as image-01-live while the stored metadata kept the original — and that value is shown in the result metadata and reused for model restore. The official docs have image-01 supporting subject_reference, so there was no reason to swap. Instead, image-01-live without a reference outside China is now rejected locally with a message saying what to do, since that combination is outside the documented range.

The web UI had no MiniMax at all. ui/src didn't mention it, so provider selection and key entry were impossible. The UI build passing wasn't evidence of the opposite — the missing unions just happened to be consistent.

Also fixed: timeouts were misclassified as network failures (AbortSignal.timeout() throws TimeoutError, not AbortError), string safety counters weren't recognised, image downloads had no size cap or content validation, and structure/01-file-function-map.md wasn't refreshed — which is what made CI fast-fail on every matrix leg.

Closing this since the work landed in #120. Appreciate the contribution.