Implements bug #194 by adding CO2 emission display by transport type:
- Add co2_by_transport_type() method to Trip class
- Display CO2 breakdown on trip list page and individual trip items
- Display CO2 breakdown on individual trip detail pages
- Show both total CO2 and breakdown by transport type (flight/train/ferry)
🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>
Implement show_flags property to conditionally display country flags for international trips. Remove unnecessary UK flags on purely UK-based trips. Closes: #183🔧 Updated templates to use show_flags property.
📝 Adjusted map and trip details to reflect flag changes.