Features:
- Add useCalculatorState hook with localStorage persistence and 1-hour expiry
- State persists through page reloads and Stripe checkout redirects
- Automatically clears state on successful payment (paid/fulfilled status)
Navigation fixes:
- Fix white page issues on checkout success/cancel pages
- Replace <a> links with button handlers for proper state-based routing
- Pass navigation handlers from App.tsx to checkout pages
State persistence integration:
- TripCalculator: Save/restore calculator inputs (fuel, distance, custom)
- MobileCalculator: Full state persistence for mobile app route
- OffsetOrder: Persist offset percentage and portfolio selection
- MobileOffsetOrder: Persist offset percentage for mobile flow
Carbon impact comparisons:
- Add varied carbon impact comparisons with random selection
- Display 3 comparisons in preview mode, 5 in success mode
- Categories: cars, flights, trees, streaming, homes
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
