[s-aga-r]

Summary

• Telemetry Alert mails use the layout of the Suite emails. Before, a mail was the alert details and a bare link.
• One template, templates/operator_emails/telemetry_alert.html, extends tenant_emails/base.html. It sets the heading and message for each alert type (Silent Host, Error Rate) and state (opened, resolved).
• A details box shows the node (hostname and IP), the opened and resolved times in the system timezone, and the alert details. A button opens the alert.
• An open Silent Host mail tells the operator to resolve the alert by hand for a node taken out of service.
• Alerts.notify renders the template and embeds the Suite icon with get_inline_images. The subject does not change.
• The template is in operator_emails/ because these mails go to the Suite Cloud operators, not to a tenant.

Screenshots

Silent Host, opened	Silent Host, resolved
Error Rate, opened	Error Rate, resolved (node without a hostname)

Test plan

• test_alerts.py checks the heading, details, link and icon of the opened mails, and the heading and Resolved row of the resolved mail.
• Ruff check and format --check pass on suite_cloud/telemetry. The 10 alert tests pass locally on the parent branch, where alerts.py, test_alerts.py and email_types.py are the same as on develop.