fix(mail): add support for BCC in email sending

config.example.yaml

@@ -27,6 +27,7 @@ email:
   smtp_pass: ""
   from: ""
   to: "" # couple's inbox, receives RSVP + photo notifications
+  bcc: "" # optional; comma-separated list of extra blind-copy recipients
 
 upload:
   max_size_mb: 15

server/internal/config/config.go

@@ -53,6 +53,7 @@ type EmailConfig struct {
 	SMTPPass string `yaml:"smtp_pass"`
 	From     string `yaml:"from"`
 	To       string `yaml:"to"`
+	Bcc      string `yaml:"bcc"` // optional; comma-separated list of extra blind-copy recipients
 }
 
 type UploadConfig struct {

server/internal/mail/mail.go

@@ -48,7 +48,14 @@ func (m *Mailer) send(subject, body string) error {
 		m.cfg.From, m.cfg.To, subject, newMessageID(m.cfg.From), time.Now().Format(time.RFC1123Z), body,
 	)
 
-	return smtp.SendMail(addr, auth, m.cfg.From, []string{m.cfg.To}, []byte(msg))
+	recipients := []string{m.cfg.To}
+	for _, bcc := range strings.Split(m.cfg.Bcc, ",") {
+		if bcc = strings.TrimSpace(bcc); bcc != "" {
+			recipients = append(recipients, bcc)
+		}
+	}
+
+	return smtp.SendMail(addr, auth, m.cfg.From, recipients, []byte(msg))
 }
 
 func (m *Mailer) SendRSVP(r store.RSVP) error {