feat: Auto resolve conversations after n days of inactivity (#1308)

fixes: #418

app/jobs/auto_resolve_conversations_job.rb

@@ -0,0 +1,16 @@
+class AutoResolveConversationsJob < ApplicationJob
+  queue_as :medium
+
+  def perform(conversation_id)
+    conversation = Conversation.find_by(id: conversation_id)
+    return unless conversation&.auto_resolve_duration && conversation&.open?
+
+    time_since_last_activity = Time.zone.now.to_i - conversation.last_activity_at.to_i
+    time_left_to_auto_resolve = conversation.auto_resolve_duration.days.to_i - time_since_last_activity
+    if time_left_to_auto_resolve.positive?
+      AutoResolveConversationsJob.set(wait_until: time_left_to_auto_resolve.seconds.from_now).perform_later(conversation_id)
+    else
+      conversation.toggle_status
+    end
+  end
+end