Make Arvan DNS updates opt-in and persist English user names.

Domain add/edit only upserts Arvan records when updateDns is true, and super-admin user PATCH now accepts firstNameEn and lastNameEn.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/domain-admin/dto/update-domain-admin.dto.ts

@@ -1,4 +1,4 @@
-import { IsDateString, IsOptional, IsString, MinLength } from 'class-validator';
+import { IsBoolean, IsDateString, IsOptional, IsString, MinLength } from 'class-validator';
 
 export class UpdateDomainAdminDto {
   @IsOptional()
@@ -9,4 +9,9 @@ export class UpdateDomainAdminDto {
   @IsOptional()
   @IsDateString()
   expiresAt?: string;
+
+  /** When true, upsert Meshkee tenant records in Arvan DNS. */
+  @IsOptional()
+  @IsBoolean()
+  updateDns?: boolean;
 }