Fix duplicate detection system - improve blocking strategy for interests

- Updated interest blocking strategy to group by name prefix instead of email domain
- This fixes the issue where interests with different email domains were never compared
- Updated admin duplicate finder to use the new centralized utility
- Both Matthew Ciaccio entries will now be detected as duplicates

server/utils/duplicate-detection.ts

@@ -342,14 +342,23 @@ export function createInterestConfig(): DuplicateDetectionConfig<any> {
   return {
     type: 'interest',
     
-    // Group by normalized email domain or phone prefix for blocking
+    // Group by normalized name prefix for blocking to catch name-based duplicates
     getKey: (interest) => {
+      // Priority 1: Use normalized name prefix (first 3 chars) to catch name duplicates
+      if (interest['Full Name']) {
+        const name = interest['Full Name'].toLowerCase().trim();
+        const prefix = name.substring(0, 3);
+        return `name_${prefix}`;
+      }
+      
+      // Priority 2: Use email domain for email-based grouping
       if (interest['Email Address']) {
         const email = normalizeEmail(interest['Email Address']);
         const domain = email.split('@')[1] || 'unknown';
         return `email_${domain}`;
       }
       
+      // Priority 3: Use phone prefix
       if (interest['Phone Number']) {
         const phone = normalizePhone(interest['Phone Number']);
         const prefix = phone.length >= 4 ? phone.substring(0, 4) : phone;