Better ordering for NC Styles in the outfit editor

Previously, when opening the pose picker and looking at Styles, the
Cybunny options were sorted like this:

- Default
- Celebratory 25th Anniversary
- Festive Christmas
- Nostalgic Baby
- Nostalgic Blue
- Nostalgic Christmas
- Nostalgic Darigan
- Nostalgic Faerie
- Nostalgic Grey
- Nostalgic Maraquan
- Nostalgic Mutant
- Nostalgic Plushie
- Nostalgic Robot
- Nostalgic Royalboy
- Nostalgic Royalgirl
- Nostalgic Snow
- Nostalgic Tyrannian
- Prismatic Cocoa: Festive Christmas
- Prismatic Cocoa: Nostalgic Christmas
- Prismatic Tinsel: Festive Christmas
- Prismatic Tinsel: Nostalgic Christmas
- Spooky Halloween

Now, they're sorted like this:

- Default
- Celebratory 25th Anniversary
- Nostalgic Baby
- Nostalgic Blue
- Festive Christmas
- Prismatic Cocoa: Festive Christmas
- Prismatic Tinsel: Festive Christmas
- Nostalgic Christmas
- Prismatic Cocoa: Nostalgic Christmas
- Prismatic Tinsel: Nostalgic Christmas
- Nostalgic Darigan
- Nostalgic Faerie
- Nostalgic Grey
- Spooky Halloween
- Nostalgic Maraquan
- Nostalgic Mutant
- Nostalgic Plushie
- Nostalgic Robot
- Nostalgic Royalboy
- Nostalgic Royalgirl
- Nostalgic Snow
- Nostalgic Tyrannian

Note especially the Christmas case, which is all together now! I think
it's also more in line with people's expectations for Halloween to be
alphabetically among the rest, instead of being at the bottom for being
"Spooky".

There's enough styles now that I'm starting to wonder if there's other
UI affordances worth having here, like e.g. only showing (or at least
prioritizing) styles that match the chosen color? But I don't want to
mislead people about compatibility, either.

app/controllers/alt_styles_controller.rb

@@ -27,8 +27,7 @@ class AltStylesController < ApplicationController
 				render
 			}
 			format.json {
-				@alt_styles = @alt_styles.includes(swf_assets: [:zone]).
+				@alt_styles = @alt_styles.includes(swf_assets: [:zone]).by_name_grouped
-					sort_by(&:full_name)
 				render json: @alt_styles.as_json(
 					only: [:id, :species_id, :color_id, :body_id, :series_name,
 								 :adjective_name, :thumbnail_url],

app/models/alt_style.rb

@@ -26,6 +26,24 @@ class AltStyle < ApplicationRecord
     #       created around midnight.
     order(Arel.sql("DATE(CONVERT_TZ(created_at, '+00:00', '-08:00')) DESC"))
   }
+  scope :by_series_main_name, -> {
+    # The main part of the series name, like "Nostalgic".
+    order(Arel.sql("SUBSTRING_INDEX(series_name, ': ', -1)"))
+  }
+  scope :by_series_variant_name, -> {
+    # The variant part of the series name, like "Prismatic Cyan".
+    order(Arel.sql("SUBSTRING_INDEX(series_name, ': ', 1)"))
+  }
+  scope :by_color_name, -> {
+    joins(:color).order(Color.arel_table[:name])
+  }
+  scope :by_name_grouped, -> {
+    # Sort by the color name, then the main part of the series name, then the
+    # variant part of the series name. This way, all the, say, Christmas colors
+    # and their Prismatic variants will be together, including both Festive and
+    # Nostalgic cases.
+    by_color_name.by_series_main_name.by_series_variant_name
+  }
   scope :unlabeled, -> { where(series_name: nil) }
   scope :newest, -> { order(created_at: :desc) }
 
@@ -106,9 +124,9 @@ class AltStyle < ApplicationRecord
   end
 
   def self.all_series_names
-    # Sort by the part *after* the colon, then before (if any).
+    distinct.where.not(series_name: nil).
-    distinct.where.not(series_name: nil).pluck(:series_name).
+      by_series_main_name.by_series_variant_name.
-      sort_by { |series_name| series_name.split(': ', 2).reverse }
+      pluck(:series_name)
   end
 
   def self.all_supported_colors