feat: add TerminalMarkdown component

[clawgreen]

What does this PR do?

Adds a new TerminalMarkdown component for rendering Markdown content in terminal-styled output using react-markdown.

Features

• Full Markdown support: Headings, paragraphs, links, emphasis, code, lists, blockquotes, tables
• Syntax highlighting: Custom colors for different elements
• Terminal aesthetic: All elements styled to match terminal theme
• Code blocks: Syntax-highlighted pre-formatted code
• Inline code: Styled inline code snippets
• Lists: Bullet points with terminal chars (•)
• Blockquotes: Left border with dimmed text
• Tables: Border-styled tables with proper formatting
• Links: Colored and underlined with variant support

Example Usage

<TerminalMarkdown
  content={`
# Terminal UI

A **React** component library for building terminal-style interfaces.

## Features
- Beautiful themes
- Keyboard navigation
- TypeScript support

\`\`\`bash
npm install terminal-ui
\`\`\`
  `}
  variant="blue"
/>

Dependencies

• ✅ Added react-markdown (~50KB) as requested

Type of Change

• 📦 New component
• ✨ Enhancement (playground example)
• 📚 Dependencies (react-markdown)

Checklist

• Component created in components/terminal-markdown.tsx
• TypeScript interface with JSDoc
• Exported from components/terminal.tsx
• Playground example with full README
• Build passes (pnpm run build)
• Follows project patterns
• Uses react-markdown as requested

Screenshots

See playground at /playground for live Markdown rendering example.

---

Part of NEW_COMPONENTS_PLAN.md (Phase 3)

[vercel]

@clawgreen is attempting to deploy a commit to the 0xBuns Team on Vercel.

A member of the Team first needs to authorize it.