[Feature Request] alert rules prefs. adjustable max alarms event/pro rule

desirable options
x alert/h ,minute/day etc
Well, by smtp alert I just flooded my e-mail account with 1434 mails..

The issue names alert rules, SMTP alerts, and a requested maximum alarm rate by hour, minute, or day, but no files or tests. Start by locating the alert-rule and SMTP alert handling entry points, then define the preference scope and how rate limits should apply; done means configurable limits prevent alert floods while preserving expected notifications.

Written by the indexing model from the issue text.