Send emails with Markdown content, attachments, and multi-recipient support via SMTP. Use when Claude needs to send emails programmatically, including scenarios like: (1) Sending notifications or reports via email, (2) Sending Markdown-formatted content as HTML emails, (3) Sending emails with attachments, (4) Sending to multiple recipients with CC/BCC, (5) Configuring SMTP for different email providers (Gmail, QQ, 163, Outlook, etc.)