fix(core): skip stream_options for providers that reject it (Cerebras 422)

[cdxiaodong]

Summary

• Fixes HTTP 422 errors when using Cerebras as an OpenAI-compatible provider. Cerebras strictly validates request parameters and rejects stream_options as an unknown field.
• Adds a shouldIncludeStreamOptions() method that checks the provider's base URL and conditionally omits stream_options for known strict providers (e.g. api.cerebras.ai).
• The fix follows the same pattern used by existing vendor-specific workarounds (DeepSeek, OpenRouter, DashScope).

Changes

• packages/core/src/core/openaiContentGenerator.ts: Added shouldIncludeStreamOptions() helper and conditionally spread stream_options in streaming requests.

Test plan

• Verify existing tests pass: npm run test --workspace @office-ai/aioncli-core
• Test streaming with Cerebras provider (OPENAI_BASE_URL=https://api.cerebras.ai/v1) — should no longer get 422
• Test streaming with OpenAI/DeepSeek/other providers — stream_options should still be included as before

[kuishou68]

@cdxiaodong Thanks for the contribution! The code change looks clean and follows the existing pattern (shouldIncludeMetadata()). A few things need to be addressed before we can merge:

Required

1. Add unit tests — Per our project conventions, all OpenAI-related changes need corresponding tests in openaiContentGenerator.test.ts. Please add tests covering:

   • Cerebras baseURL (https://api.cerebras.ai/v1) → stream_options should be omitted
   • Normal providers (OpenAI, DeepSeek, etc.) → stream_options should still be included
   • Invalid/empty URL fallback → should default to including stream_options

2. Trigger CI — There are no CI checks on this branch yet. Please ensure npm run build && npm run test passes.

Optional (nice-to-have)

3. Consider extracting strictProviders into a shared constant or config if we expect more providers to be added over time. Not a blocker for this PR though.

4. The .endsWith('.' + h) subdomain matching for api.cerebras.ai is unlikely to match in practice, but it's harmless so fine to keep.

Overall the fix is small, safe, and well-scoped. Just need the tests and a green CI run to proceed. 👍

[cdxiaodong]

修复并提交新commit id为：45f92016a7c214a7aaebc3b0afdbe380056acdc4
单测通过图

修复前后对比日志