feat: Implement replyTo for contact form emails and refine success/error message layout.

lib/mail/mailer.ts

@@ -27,16 +27,18 @@ function getTransporter() {
 
 interface SendEmailOptions {
   to?: string | string[];
+  replyTo?: string;
   subject: string;
   html: string;
 }
 
-export async function sendEmail({ to, subject, html }: SendEmailOptions) {
+export async function sendEmail({ to, replyTo, subject, html }: SendEmailOptions) {
   const recipients = to || config.mail.recipients;
 
   const mailOptions = {
     from: config.mail.from,
     to: recipients,
+    replyTo,
     subject,
     html,
   };