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

- `.env.production.sample`:
  Our sample config file is very different from upstream since it is much more
  complete. Upstream added documentation for a few env variables.
  Copied the new variables/documentation from upstream.
- `app/lib/feed_manager.rb`:
  Upstream added a timeline type (hashtags), while glitch-soc already had an
  extra one (direct messages). Not really a conflict but textually close
  changes.
  Ported upstream's changes.
- `app/models/custom_emoji.rb`:
  Upstream upped the custom emoji size limit, while glitch-soc had configurable
  limits.
  Upped the default limits accordingly.
- `streaming/index.js`:
  Upstream reworked how hastags were normalized. Minor conflict due to
  glitch-soc's handling of instance-local posts.
  Ported upstream's changes.

app/views/accounts/show.html.haml

@@ -75,7 +75,7 @@
           = link_to short_account_tag_path(@account, featured_tag.tag) do
             %h4
               = fa_icon 'hashtag'
-              = featured_tag.name
+              = featured_tag.display_name
               %small
                 - if featured_tag.last_status_at.nil?
                   = t('accounts.nothing_here')

app/views/accounts/show.rss.ruby

@@ -28,7 +28,7 @@ RSS::Builder.build do |doc|
       end
 
       status.tags.each do |tag|
-        item.category(tag.name)
+        item.category(tag.display_name)
       end
     end
   end