CurrentUser object uses user_id attribute, not id. Caused AttributeError
on PUT /api/settings/smtp.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
When use_tls=false, the old logic set start_tls=true for any port != 25,
which broke plain SMTP servers like Mailpit. Now:
- Port 465: implicit TLS
- use_tls=true on other ports: STARTTLS
- use_tls=false: plain SMTP (no TLS)
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>