- Add listAvailableModels() and validateModel() to openai.ts
- Improve testOpenAIConnection() to test configured model
- Add checkAIStatus endpoint to filtering router
- Add pre-execution AI config check in executeRules
- Improve error messages in AI filtering service (rate limit, quota, etc.)
- Add AI status warning banner on round detail page for filtering rounds
Now admins get clear errors when AI is misconfigured instead of silent flags.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>