Custom emoji, downvotes, blurhash and focal points on the cards

What other platforms send now shows as they meant it:
- custom emoji (a post's or account's :shortcode:) as their pictures in
  posts, names, content warnings, bios and fields: only the shortcodes the
  server listed, only http(s) pictures, never inside a tag, the shortcode
  kept as alt text;
- a threadiverse post's downvotes next to its favourites;
- blurhash placeholders until a picture loads (wwwroot/js/blurhash.js, a
  small decoder that watches the page), and a picture's focal point;
- an event's online link, participants and capacity, and whether it is
  tentative or cancelled.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LsXgEaXee4GCU1hwYgPJXw

Resources/AllStrings.resx

@@ -1577,4 +1577,22 @@
   <data name="The event&#x27;s server shows who takes part, {0} included. Your other personas are never named." xml:space="preserve">
     <value>The event's server shows who takes part, {0} included. Your other personas are never named.</value>
   </data>
+  <data name="Downvotes" xml:space="preserve">
+    <value>Downvotes</value>
+  </data>
+  <data name="Online" xml:space="preserve">
+    <value>Online</value>
+  </data>
+  <data name="{0} going" xml:space="preserve">
+    <value>{0} going</value>
+  </data>
+  <data name="{0} of {1} going" xml:space="preserve">
+    <value>{0} of {1} going</value>
+  </data>
+  <data name="Cancelled" xml:space="preserve">
+    <value>Cancelled</value>
+  </data>
+  <data name="Tentative" xml:space="preserve">
+    <value>Tentative</value>
+  </data>
 </root>