feat(structure): Use unified Email class

ts/mail/core/classes.email.ts

@@ -640,6 +640,34 @@ export class Email {
     return this.from;
   }
   
+  /**
+   * Get the subject (Smartmail compatibility method)
+   * @returns The email subject
+   */
+  public getSubject(): string {
+    return this.subject;
+  }
+  
+  /**
+   * Get the body content (Smartmail compatibility method)
+   * @param isHtml Whether to return HTML content if available
+   * @returns The email body (HTML if requested and available, otherwise plain text)
+   */
+  public getBody(isHtml: boolean = false): string {
+    if (isHtml && this.html) {
+      return this.html;
+    }
+    return this.text;
+  }
+  
+  /**
+   * Get the from address (Smartmail compatibility method)
+   * @returns The sender email address
+   */
+  public getFrom(): string {
+    return this.from;
+  }
+  
   /**
    * Get the message ID
    * @returns The message ID