Part of #822

Summary

Enable the Docusaurus blog feature for release notes, announcements, and community updates.

Current State

Blog is explicitly disabled in website/docusaurus.config.ts:

blog: false,

Scope

• Set blog: true in preset options (or configure blog settings)
• Create /website/blog/ directory structure
• Add initial blog post template or placeholder
• Add blog link to navbar navigation
• Configure blog metadata (authors, tags, etc.)