Added plan.md with complete architecture for format-agnostic content generation:
- Support for Markdown, HTML, Plain Text, JSON formats
- New FormatExporter module with neutral data structure
- Integration strategy with existing ContentAssembly and ArticleStorage
- Bonus features: SEO metadata generation, readability scoring, WordPress Gutenberg format
- Implementation roadmap with 4 phases (6h total estimated)
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
