Studio plugin removed, cleaner Insights transcripts

The Studio plugin (@sanity/context/studio) is removed, so installing @sanity/context for Insights no longer adds Studio to your app, and it works in React 18 apps. Still using the plugin? Stay on @sanity/context@^2, or see Migrate from the Context Studio plugin to the new Context app.

Saved transcripts now contain only user text, assistant text, and tool calls. On AI SDK v7, provider metadata was being saved as JSON in assistant messages. No code changes are needed if you only use Insights. See Add insights to Sanity Context.