fix(mail): harden mailer and fix missing notification recipients

lib/env.ts

@@ -42,7 +42,7 @@ const envExtension = {
   MAIL_USERNAME: z.string().optional(),
   MAIL_PASSWORD: z.string().optional(),
   MAIL_FROM: z.string().optional(),
-  MAIL_RECIPIENTS: z.string().optional(),
+  MAIL_RECIPIENTS: z.string().trim().optional(),
 };
 
 /**

lib/mail/mailer.ts

@@ -32,16 +32,27 @@ interface SendEmailOptions {
 }
 
 export async function sendEmail({ to, replyTo, subject, html }: SendEmailOptions) {
-  const recipients = to || config.mail.recipients;
   const logger = getServerAppServices().logger.child({ component: 'mailer' });
+  
+  // Resolve recipients: priority to 'to' override, fallback to global MAIL_RECIPIENTS
+  const resolvedTo = to || config.mail.recipients;
+  
+  // Normalize recipients (handle arrays or comma-strings)
+  const recipients = Array.isArray(resolvedTo) 
+    ? resolvedTo.join(', ') 
+    : (resolvedTo?.toString() || '');
 
-  if (!recipients) {
-    logger.error('No email recipients configured (MAIL_RECIPIENTS is empty and no "to" provided)', { subject });
+  if (!recipients || recipients.trim() === '') {
+    logger.error('Email delivery ABORTED: No recipients configured', { 
+      subject, 
+      providedTo: to,
+      configRecipients: config.mail.recipients 
+    });
     return { success: false as const, error: 'No recipients configured' };
   }
 
   if (!config.mail.from) {
-    logger.error('MAIL_FROM is not configured — cannot send email', { subject, recipients });
+    logger.error('Email delivery ABORTED: MAIL_FROM is missing', { subject, recipients });
     return { success: false as const, error: 'MAIL_FROM is not configured' };
   }
 
@@ -53,14 +64,36 @@ export async function sendEmail({ to, replyTo, subject, html }: SendEmailOptions
     html,
   };
 
-
   try {
-    const info = await getTransporter().sendMail(mailOptions);
-    logger.info('Email sent successfully', { messageId: info.messageId, subject, recipients });
+    const transporter = getTransporter();
+    logger.info('Attempting to send email via SMTP', { 
+      host: config.mail.host,
+      subject, 
+      recipients,
+      hasReplyTo: !!replyTo 
+    });
+
+    const info = await transporter.sendMail(mailOptions);
+    
+    logger.info('Email sent successfully', { 
+      messageId: info.messageId, 
+      subject, 
+      recipients,
+      response: info.response 
+    });
+    
     return { success: true, messageId: info.messageId };
   } catch (error) {
     const errorMsg = error instanceof Error ? error.message : String(error);
-    logger.error('Error sending email', { error: errorMsg, subject, recipients });
+    logger.error('SMTP Transport failed', { 
+      error: errorMsg, 
+      subject, 
+      recipients,
+      config: {
+        host: config.mail.host,
+        user: config.mail.user ? '***' : 'not set'
+      }
+    });
     return { success: false, error: errorMsg };
   }
 }