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

Conflicts:
- `.github/dependabot.yml`:
  Updated upstream, removed in glitch-soc to disable noise.
  Kept removed.
- `CODE_OF_CONDUCT.md`:
  Upstream updated to a new version of the covenant, but I have not read it
  yet, so kept unchanged.
- `Gemfile.lock`:
  Not a real conflict, one upstream dependency updated textually too close to
  the glitch-soc only `hcaptcha` dependency.
  Applied upstream changes.
- `app/controllers/admin/base_controller.rb`:
  Minor conflict due to glitch-soc's theming system.
  Applied upstream changes.
- `app/controllers/application_controller.rb`:
  Minor conflict due to glitch-soc's theming system.
  Applied upstream changes.
- `app/controllers/disputes/base_controller.rb`:
  Minor conflict due to glitch-soc's theming system.
  Applied upstream changes.
- `app/controllers/relationships_controller.rb`:
  Minor conflict due to glitch-soc's theming system.
  Applied upstream changes.
- `app/controllers/statuses_cleanup_controller.rb`:
  Minor conflict due to glitch-soc's theming system.
  Applied upstream changes.
- `app/helpers/application_helper.rb`:
  Minor conflict due to glitch-soc's theming system.
  Applied upstream changes.
- `app/javascript/mastodon/features/compose/components/compose_form.jsx`:
  Upstream added a highlight animation for onboarding, while we changed the
  max character limit.
  Applied our local changes on top of upstream's new version.
- `app/views/layouts/application.html.haml`:
  Minor conflict due to glitch-soc's theming system.
  Applied upstream changes.
- `stylelint.config.js`:
  Upstream added ignore paths, glitch-soc had extra ignore paths.
  Added the same paths as upstream.

app/controllers/concerns/web_app_controller_concern.rb

@@ -7,6 +7,12 @@ module WebAppControllerConcern
     prepend_before_action :redirect_unauthenticated_to_permalinks!
     before_action :set_pack
     before_action :set_app_body_class
+
+    vary_by 'Accept, Accept-Language, Cookie'
+  end
+
+  def skip_csrf_meta_tags?
+    current_user.nil?
   end
 
   def set_app_body_class