0.0.3

Add syntax highlighting and copy buttons to chat UI

- Replace marked.js with markdown-it for better markdown parsing
- Add highlight.js with GitHub theme for syntax highlighting
- Add Font Awesome for icons
- Add copy buttons to code blocks and blockquotes
- Style blockquotes with GitHub-like appearance (gray background, left border)
- Style code blocks with GitHub-like appearance

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>