Aggiunge sulla dashboard invii il KPI mail/ora dagli invii SMTP confermati.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/services/mailings/hourly_throughput.rb

@@ -0,0 +1,35 @@
+class Mailings::HourlyThroughput
+  HOUR = 1.hour
+  RECENT = 15.minutes
+
+  def initialize(project, now: Time.current)
+    @project = project
+    @now = now
+  end
+
+  def sent
+    @sent ||= sent_since(HOUR)
+  end
+
+  def recent_sent
+    @recent_sent ||= sent_since(RECENT)
+  end
+
+  def failed
+    @failed ||= recipients.failed.where(updated_at: (@now - HOUR)..@now).count
+  end
+
+  def drained
+    sent + failed
+  end
+
+  private
+
+  def sent_since(window)
+    recipients.sent.where(sent_at: (@now - window)..@now).count
+  end
+
+  def recipients
+    MailingRecipient.joins(:mailing).merge(Mailing.for_project(@project))
+  end
+end