docs(sqlite-studio): connect Docs Cloud

[farming-labs-docs]

Connects Kinfe123/sqlite-studio to Docs Cloud without replacing the existing docs app.

This PR adds:

• docs.json with Docs Cloud publishing, API key, and analytics config.
• docs.config.ts (or the existing docs.config.*) with runtime analytics enabled.
• .env.docs-cloud.example as a safe reference for the production env vars.
• DOCS_CLOUD_SETUP.md with the API key, project id, and production environment checklist.

After merge:

1. Create an API key in Docs Cloud Settings -> API Keys.
2. Create or open the Docs Cloud analytics project for this repository and copy its project id.
3. Add DOCS_CLOUD_API_KEY and NEXT_PUBLIC_DOCS_CLOUD_PROJECT_ID to production using .env.production, CI secrets, or the hosting provider's environment variables.
4. The docs runtime uses the project id to attach the Docs Cloud event handler automatically. Existing analytics.onEvent callbacks keep running.
5. Keep the real key out of git.

Docs root: docs

Reference: https://docs.farming-labs.dev
Generated by Docs Cloud.