Aggiunge pulsante per fermare un invio email in corso.

Permette di annullare i destinatari ancora in coda mantenendo le email già inviate.

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

app/models/mailing.rb

@@ -72,6 +72,10 @@ class Mailing < ApplicationRecord
     status == "sent"
   end
 
+  def cancelled?
+    status == "cancelled"
+  end
+
   def editable?
     draft?
   end
@@ -187,6 +191,17 @@ class Mailing < ApplicationRecord
     update!(status: "sent", completed_at: Time.current, next_send_at: nil)
   end
 
+  def cancel_send!
+    raise "Solo un invio in corso può essere fermato" unless sending?
+
+    transaction do
+      mailing_recipients.where(status: %w[pending queued]).find_each do |recipient|
+        recipient.update!(status: "skipped", skip_reason: "invio annullato")
+      end
+      update!(status: "cancelled", next_send_at: nil, completed_at: Time.current)
+    end
+  end
+
   private
 
   def send_window_order