Fix spatial variability and annual climate for suitability maps; improve planting calendar visualization

[manasasharma1410]

Summary

The current Shiny app for crop suitability is improved but still has issues:

• Suitability maps show only one color per district (no spatial variability)
• Both temperature and precipitation should use annual averages/totals for suitability maps, not just precipitation
• Planting calendar visualization can be improved for clarity and usability
• Ensemble means per grid cell are available and should drive the spatial maps

Details

Problems

1. No spatial variability:
   • The suitability maps are not showing differences across grid cells within districts (all grid cells have same color).
   • This suggests annual means are being calculated incorrectly or