The Do-Not-Disturb registry — GET <dashboard_path>/suppressions.
Lists SquatchMail.Suppression rows (bounces, complaints, and manual
entries), lets an operator add a manual suppression, remove any row, and
release expired soft bounces in bulk.
Reason filter via query params
handle_params/3 reads a ?reason= query param (hard_bounce,
soft_bounce, complaint, or manual) and pre-applies it as the reason
filter, so links can deep-link into a single category. Note this filters
suppressions — the sidebar's dedicated Bounces/Complaints pages
(/bounces, /complaints, served by SquatchMail.Web.Live.TrailLog) list
the bounced/complained emails instead.