feat: implement heat map visualization with Leaflet.heat plugin
- Integrate Leaflet.heat plugin for heat map overlay
- Add heat map toggle control in MapFilters component
- Configure heat map intensity based on report quantity levels (minimal: 0.3, moderate: 0.5, significant: 0.7, severe: 1.0)
- Implement heat map layer management with proper cleanup
- Add custom gradient colors (blue to red) for visual intensity representation
- Configure heat map with radius: 25px, blur: 15, maxZoom: 17
- Add TypeScript type declarations for leaflet.heat
- Heat map respects existing filter state (date range, litter type, quantity)
Implements task 5: Create heat map visualization
Requirements: 3.1, 3.5
Paul Bailey
8f297e1ec4