docs: add remaining docs for classes in app/logical.

app/jobs/application_job.rb

@@ -1,3 +1,7 @@
+# The base class for all background jobs on Danbooru.
+#
+# @see https://guides.rubyonrails.org/active_job_basics.html
+# @see https://github.com/collectiveidea/delayed_job
 class ApplicationJob < ActiveJob::Base
   queue_as :default
   queue_with_priority 0

app/jobs/delete_favorites_job.rb

@@ -1,3 +1,4 @@
+# A job that deletes a user's favorites when they delete their account.
 class DeleteFavoritesJob < ApplicationJob
   queue_as :default
   queue_with_priority 20

app/jobs/delete_post_files_job.rb

@@ -1,3 +1,5 @@
+# A job that deletes a post's files after it's replaced, or a preprocessed
+# upload is never completed.
 class DeletePostFilesJob < ApplicationJob
   queue_as :default
   queue_with_priority 20

app/jobs/regenerate_post_job.rb

@@ -1,3 +1,4 @@
+# A job that regenerates a post's images and IQDB when a moderator requests it.
 class RegeneratePostJob < ApplicationJob
   queue_as :default
   queue_with_priority 20

app/jobs/tag_batch_change_job.rb

@@ -1,3 +1,5 @@
+# A job that performs a mass update or tag nuke operation in a bulk update
+# request.
 class TagBatchChangeJob < ApplicationJob
   queue_as :bulk_update
 

app/jobs/tag_rename_job.rb

@@ -1,3 +1,5 @@
+# A job that performs a tag rename or alias operation in a bulk update request.
+# Jobs in the `bulk_update` queue are processed sequentially.
 class TagRenameJob < ApplicationJob
   queue_as :bulk_update
 

app/jobs/upload_preprocessor_delayed_start_job.rb

@@ -1,3 +1,5 @@
+# A job that downloads and generates thumbnails in the background for an image
+# uploaded with the upload bookmarklet.
 class UploadPreprocessorDelayedStartJob < ApplicationJob
   queue_as :default
   queue_with_priority(-1)

app/jobs/upload_service_delayed_start_job.rb

@@ -1,3 +1,4 @@
+# A job that tries to resume a preprocessed image upload.
 class UploadServiceDelayedStartJob < ApplicationJob
   queue_as :default
   queue_with_priority(-1)