9d4942aef6
Three HTMX-polled monitoring screens (spec 7.2.11-13): send log with server-side domain/application filters and pagination, Postfix queue (postqueue -p), and a mail.log tail. Fragment endpoints return HTML snippets, not JSON (spec 7.1); all output is auto-escaped via html/template (spec 7.6.7). Adds store.QuerySendLog/CountSendLog/ListApplicationLogins, postfix.Queue(), and logtail.TailLines (a point-in-time reverse read, independent of the background follow loop). Verified on the dev server: gofmt/vet/test green, docker build green, container e2e (filters, 60-row pagination, <script> escaping, real postqueue/mail.log output, existing Reload button unaffected). Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>