Merge branch 'main' into glitch-soc/merge-upstream

Conflicts:
- `README.md`:
  Upstream updated its README, while we have a completely different one.
  Kept our README.
- `app/controllers/concerns/web_app_controller_concern.rb`:
  Conflict because of glitch-soc's theming system.
  Additionally, glitch-soc has different behavior regarding moved accounts.
  Ported some of the changes, but kept our overall behavior.
- `app/javascript/packs/admin.js`:
  Code changes actually applied to `app/javascript/core/admin.js`

app/serializers/rest/preferences_serializer.rb

@@ -7,6 +7,7 @@ class REST::PreferencesSerializer < ActiveModel::Serializer
 
   attribute :reading_default_sensitive_media, key: 'reading:expand:media'
   attribute :reading_default_sensitive_text, key: 'reading:expand:spoilers'
+  attribute :reading_autoplay_gifs, key: 'reading:autoplay:gifs'
 
   def posting_default_privacy
     object.user.setting_default_privacy
@@ -27,4 +28,8 @@ class REST::PreferencesSerializer < ActiveModel::Serializer
   def reading_default_sensitive_text
     object.user.setting_expand_spoilers
   end
+
+  def reading_autoplay_gifs
+    object.user.setting_auto_play_gif
+  end
 end