related tags: add AI tags to related tags section.

Add a Suggested tags list to the Related Tags box. The suggested tags
are just the AI tags for the post.

Suggested tags are currently hidden in CSS for beta testing. Use custom
CSS to unhide them.

app/logical/related_tag_query.rb

@@ -6,12 +6,13 @@ class RelatedTagQuery
   include ActiveModel::Serializers::JSON
   include ActiveModel::Serializers::Xml
 
-  attr_reader :query, :post_query, :category, :type, :user, :limit
+  attr_reader :query, :post_query, :media_asset, :category, :type, :user, :limit
 
-  def initialize(query:, user: User.anonymous, category: nil, type: nil, limit: nil)
+  def initialize(query:, media_asset: nil, user: User.anonymous, category: nil, type: nil, limit: nil)
     @user = user
     @post_query = PostQuery.normalize(query, current_user: user) # XXX This query does not include implicit metatags (rating:s, -status:deleted)
     @query = @post_query.to_s
+    @media_asset = media_asset
     @category = category
     @type = type
     @limit = (limit =~ /^\d+/ ? limit.to_i : 25)
@@ -55,6 +56,11 @@ class RelatedTagQuery
     @similar_tags ||= RelatedTagCalculator.similar_tags_for_search(post_query, category: category_of).take(limit)
   end
 
+  def ai_tags
+    return AITag.none if media_asset.nil?
+    media_asset.ai_tags.joins(:tag).undeprecated.nonempty.in_order_of(:"tags.category", TagCategory.canonical_mapping.values).order("ai_tags.score DESC, tags.name ASC").take(limit)
+  end
+
   # Returns the top 20 most frequently added tags within the last 20 edits made by the user in the last hour.
   def recent_tags(since: 1.hour.ago, max_edits: 20, max_tags: 20)
     return [] unless user.present? && PostVersion.enabled?