feat: use saveChatCompletion in handleChatStream to match handleChatGenerate (MYC-3962)

[sweetmantech]

Summary

• Replace handleChatCompletion with saveChatCompletion in handleChatStream to match /api/chat/generate behavior
• Remove duplicate room creation and user message persistence (now handled in validateChatRequest -> setupConversation)
• Keep assistant message persistence with proper error handling (non-critical, logs errors but doesn't fail the request)

Test plan

• Unit tests pass for handleChatStream (11 tests)
• New tests added for message persistence in onFinish callback:
  • Calls saveChatCompletion with text from last assistant message
  • Uses responseMessage as fallback when no assistant messages
  • Does not call saveChatCompletion when stream is aborted
  • Logs error but does not throw when saveChatCompletion fails
• All 564 tests pass

🤖 Generated with Claude Code

[cursor]

You have run out of free Bugbot PR reviews for this billing cycle. This will reset on February 17.

To receive reviews on all of your PRs, visit the Cursor dashboard to activate Pro and start your 14-day free trial.

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Review	Updated (UTC)
recoup-api	Ready	Preview	Jan 19, 2026 6:47pm

[coderabbitai]

Important

Review skipped

Auto reviews are disabled on base/target branches other than the default branch.

Please check the settings in the CodeRabbit UI or the .coderabbit.yaml file in this repository. To trigger a single review, invoke the @coderabbitai review command.

You can disable this status message by setting the reviews.review_status to false in the CodeRabbit configuration file.

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[sweetmantech]

Closing PR as requested