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

Conflicts:
- `README.md`:
  Upstream changed their README, we have our own.
  Kept ours.
- `app/helpers/application_helper.rb`:
  Minor code style fix upstream, on a line that is different in glitch-soc
  due to the different theming system.
  Applied the code style fix to our own code.
- `app/views/settings/preferences/appearance/show.html.haml`:
  Code style fix on a line next to lines exclusive to glitch-soc.
  Applied upstream changes.
- `yarn.lock`:
  Upstream updated a dependency textually close to a glitch-soc-only
  dependency.
  Updated the dependency like upstream did.

config/environments/production.rb

@@ -19,27 +19,16 @@ Rails.application.configure do
   # or in config/master.key. This key is used to decrypt credentials (and other encrypted files).
   # config.require_master_key = true
 
-  # Disable serving static files from the `/public` folder by default since
-  # Apache or NGINX already handles this.
-  config.public_file_server.enabled = ENV['RAILS_SERVE_STATIC_FILES'].present?
-
   ActiveSupport::Logger.new(STDOUT).tap do |logger|
     logger.formatter = config.log_formatter
     config.logger = ActiveSupport::TaggedLogging.new(logger)
   end
 
-  # Compress JavaScripts and CSS.
-  # config.assets.js_compressor = Uglifier.new(mangle: false)
-  # config.assets.css_compressor = :sass
-
   # Do not fallback to assets pipeline if a precompiled asset is missed.
   config.assets.compile = false
 
-  # `config.assets.precompile` and `config.assets.version` have moved to config/initializers/assets.rb
-
   # Specifies the header that your server uses for sending files.
-  # config.action_dispatch.x_sendfile_header = 'X-Sendfile' # for Apache
-  config.action_dispatch.x_sendfile_header = 'X-Accel-Redirect' # for NGINX
+  config.action_dispatch.x_sendfile_header = ENV['SENDFILE_HEADER'] if ENV['SENDFILE_HEADER'].present?
 
   # Allow to specify public IP of reverse proxy if it's needed
   config.action_dispatch.trusted_proxies = ENV['TRUSTED_PROXY_IP'].split(/(?:\s*,\s*|\s+)/).map { |item| IPAddr.new(item) } if ENV['TRUSTED_PROXY_IP'].present?
@@ -67,7 +56,7 @@ Rails.application.configure do
 
   # Enable locale fallbacks for I18n (makes lookups for any locale fall back to
   # English when a translation cannot be found).
-  config.i18n.fallbacks = [:en]
+  config.i18n.fallbacks = true
 
   # Send deprecation notices to registered listeners.
   config.active_support.deprecation = :notify