Contact form: SMTP_FROM=hello@where-woof.com (SES-ready), add Reply-To

frontend/internal/handlers/promo.go

@@ -72,6 +72,13 @@ func sendContactEmail(name, email, subject, message string) error {
 	if port == "" {
 		port = "587"
 	}
+	// Sender address on the envelope + From header. Defaults to hello@where-woof.com
+	// (SES verified identity). For Gmail SMTP this is ignored/overridden by the
+	// authenticated user, so it stays safe either way.
+	from := os.Getenv("SMTP_FROM")
+	if from == "" {
+		from = "hello@where-woof.com"
+	}
 
 	subj := subject
 	if subj == "" {
@@ -80,7 +87,8 @@ func sendContactEmail(name, email, subject, message string) error {
 	body := fmt.Sprintf("From: %s <%s>\nSubject: %s\n\n%s", name, email, subj, message)
 
 	msg := []byte("To: " + to + "\r\n" +
-		"From: " + user + "\r\n" +
+		"From: " + from + "\r\n" +
+		"Reply-To: " + email + "\r\n" +
 		"Subject: " + subj + "\r\n" +
 		"MIME-Version: 1.0\r\n" +
 		"Content-Type: text/plain; charset=utf-8\r\n" +
@@ -88,5 +96,5 @@ func sendContactEmail(name, email, subject, message string) error {
 
 	addr := host + ":" + port
 	auth := smtp.PlainAuth("", user, pass, host)
-	return smtp.SendMail(addr, auth, user, []string{to}, msg)
+	return smtp.SendMail(addr, auth, from, []string{to}, msg)
 }