fix(email-validator): improve MX record validation and update project configuration

ts/smartmail.classes.emailaddressvalidator.ts

@@ -101,7 +101,12 @@ export class EmailAddressValidator {
       }
     }
     
-    const result = await this.smartdns.getRecords(domain, 'MX');
+    let result: any;
+    try {
+      result = await this.smartdns.getRecords(domain, 'MX');
+    } finally {
+      this.smartdns.destroy();
+    }
     
     if (this.options.cacheDnsResults) {
       this.dnsCache.set(domain, { result, timestamp: Date.now() });
@@ -124,10 +129,7 @@ export class EmailAddressValidator {
     
     // Extract exchange values from MX records
     return mxRecords.map((record: any) => {
-      if (record && record.exchange) {
-        return record.exchange;
-      }
-      return '';
+      return record?.value || record?.exchange || '';
     }).filter(Boolean);
   }
 
@@ -221,9 +223,9 @@ export class EmailAddressValidator {
     
     // Check MX records
     const mxRecords = await this.checkMxRecords(domainPart);
-    result.mxValid = !!mxRecords;
+    result.mxValid = Array.isArray(mxRecords) && mxRecords.length > 0;
     
-    if (!mxRecords) {
+    if (!result.mxValid) {
       result.reason = 'Domain does not have valid MX records';
       return result;
     }