post_versions.tags_json への移行 (#354) (#415)

画面テストまだ．

Reviewed-on: #415
Co-authored-by: miteruzo <miteruzo@naver.com>

backend/app/controllers/posts_controller.rb

@@ -699,7 +699,10 @@ class PostsController < ApplicationController
   end
 
   def editable_tag_names_from_version version
-    version.tags.to_s.split.reject { |name| name.downcase.start_with?('nico:') }.sort
+    version.tags_json
+        .reject { _1.fetch('category') == 'nico' }
+        .map { Post.tag_snapshot_literal(_1) }
+        .sort
   end
 
   def post_snapshot_from_record post