Implemented comprehensive gum-based interactive tool selection for Level 3 menu.
Features:
- Added gum_multi_select() function to utils.py with proper type hints
- Implemented install_category_selected() in toolbelt.py
- Interactive multi-select for APT, Go, /opt, Python, and Docker categories
- Graceful fallback when gum is not installed
- Confirmation prompt before installation
- Updated README with gum usage examples
- Added PYTHON_STANDARDS.md for type hint requirements
- Created TODO.md with v2.1+ enhancement roadmap
- Added project branding images
User can now:
1. Browse categories and see tool counts
2. Use SPACE to toggle tools, ENTER when done
3. Review selected tools before installing
4. Get helpful prompts if gum is missing
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
