Adds `README.md` to `apps/studio/evals` explaining the development
workflow for updating offline and online evals for Studio's AI
Assistant.
Resolves AI-681
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## Summary by CodeRabbit
* **Documentation**
* Added comprehensive documentation for Studio Assistant Evals, covering
evaluation setup, configuration of scoring methods, and deployment
workflows for both offline and online evaluation processes.
[](https://app.coderabbit.ai/change-stack/supabase/supabase/pull/45840)
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