Geospatial Property Valuation Heatmap with Leaflet Integration

Create a Google Sheets script that uses Leaflet.js to dynamically generate a geospatial property valuation heatmap. The script should pull real-time property data from a Sheet, calculate price per square foot, and render interactive color-coded markers representing property values across different neighborhoods. Include logic to handle outliers and normalize data visualization. Implement a custom color gradient from green (undervalued) to red (overvalued) with tooltips showing detailed property metrics.