Extend pricing calculator slider max to 20 million EGP

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

public/js/main.js

@@ -733,8 +733,8 @@ function initPricingCalc() {
   const currencyLabel = isSA ? 'ر.س' : 'ج.م';
 
   const minCollections = 10000;
-  const maxCollections = 500000;
-  const step = 5000;
+  const maxCollections = 20000000;
+  const step = 10000;
 
   function formatAmount(amount) {
     return new Intl.NumberFormat('ar-EG', { style: 'currency', currency: currencyCode, maximumFractionDigits: 0 }).format(amount);