do to formatters

apps/website/lib/formatters/NumberFormatter.ts

@@ -0,0 +1,31 @@
+/**
+ * NumberDisplay
+ * 
+ * Deterministic number formatting for display.
+ * Avoids Intl and toLocaleString to prevent SSR/hydration mismatches.
+ */
+
+export class NumberFormatter {
+  /**
+   * Formats a number with thousands separators (commas).
+   * Example: 1234567 -> "1,234,567"
+   */
+  static format(value: number): string {
+    const parts = value.toString().split('.');
+    parts[0] = parts[0].replace(/\B(?=(\d{3})+(?!\d))/g, ',');
+    return parts.join('.');
+  }
+
+  /**
+   * Formats a number in compact form (e.g., 1.2k, 1.5M).
+   */
+  static formatCompact(value: number): string {
+    if (value >= 1000000) {
+      return `${(value / 1000000).toFixed(1)}M`;
+    }
+    if (value >= 1000) {
+      return `${(value / 1000).toFixed(1)}k`;
+    }
+    return value.toString();
+  }
+}