fix(mailer): add TLS settings for internal SMTP relay

- rejectUnauthorized: false (relay cert is for mail.keylinkit.net, not 172.17.0.1)
- connection/greeting/socket timeouts for reliability

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

server/mailer.js

@@ -17,6 +17,10 @@ if (SMTP_HOST && SMTP_USER && SMTP_PASS) {
     port: SMTP_PORT,
     secure: SMTP_PORT === 465,
     auth: { user: SMTP_USER, pass: SMTP_PASS },
+    connectionTimeout: 10_000,
+    greetingTimeout: 10_000,
+    socketTimeout: 15_000,
+    tls: { rejectUnauthorized: false }, // tunnel relay cert is for mail.keylinkit.net, not 172.17.0.1
   })
   console.log(`[mailer] SMTP configured: ${SMTP_HOST}:${SMTP_PORT}`)
 } else {