feat: Add Claude Code terminal integration to dashboard

- Add embedded Claude Code terminal with xterm.js for full CLI experience
- Create WebSocket PTY backend for real-time terminal communication
- Add terminal status endpoint to check CLI availability
- Update dashboard to use Claude Code terminal instead of API chat
- Add optimization control panel with start/stop/validate actions
- Add study context provider for global state management
- Update frontend with new dependencies (xterm.js addons)
- Comprehensive README documentation for all new features

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

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

atomizer-dashboard/frontend/tailwind.config.js

@@ -16,7 +16,9 @@ export default {
           500: '#334155',
           600: '#1e293b',
           700: '#0f172a',
+          750: '#0a1120',
           800: '#020617',
+          850: '#010410',
           900: '#000000',
         },
         primary: {