FEATURE: Add automation statistics tracking to Automation (#31921)

introduces comprehensive statistics tracking for the Discourse
Automation plugin, allowing users to monitor the performance and
execution patterns of their automations:

- Add `discourse_automation_stats` table to track execution metrics
including run counts, execution times, and performance data
- Create a new `Stat` model to handle tracking and retrieving automation
statistics
- Update the admin UI to display automation stats (runs today/this
week/month and last run time)
- Modernize the automation list interface using Glimmer components
- Replace the older enable/disable icon with a toggle switch for better
UX
- Add schema annotations to existing models for better code
documentation
- Include extensive test coverage for the new statistics functionality

This helps administrators understand how their automations are
performing and identify potential bottlenecks or optimization
opportunities.

---------

Co-authored-by: Joffrey JAFFEUX <j.jaffeux@gmail.com>
Co-authored-by: Ted Johansson <ted@discourse.org>

plugins/automation/app/models/discourse_automation/pending_automation.rb

@@ -7,3 +7,14 @@ module DiscourseAutomation
     belongs_to :automation, class_name: "DiscourseAutomation::Automation"
   end
 end
+
+# == Schema Information
+#
+# Table name: discourse_automation_pending_automations
+#
+#  id            :bigint           not null, primary key
+#  automation_id :bigint           not null
+#  execute_at    :datetime         not null
+#  created_at    :datetime         not null
+#  updated_at    :datetime         not null
+#