Add Stationery and Stationery Dark themes with notebook chrome.

Manila folders, ruled chat, post-it nav, and folder tabs; dark variant uses Catppuccin Mocha colors with muted stickies and soft glows.

src/app/plugins/react-custom-html-parser.tsx

@@ -104,6 +104,7 @@ export const renderMatrixMention = (
         {...customProps}
         className={css.Mention({ highlight: mx.getUserId() === userId })}
         data-mention-id={userId}
+        data-mention-self={mx.getUserId() === userId ? '' : undefined}
       >
         {`@${
           (currentRoom && getMemberDisplayName(currentRoom, userId)) ?? getMxIdLocalPart(userId)
@@ -213,7 +214,7 @@ export const highlightText = (
       text,
       regex,
       (match, pushIndex) => (
-        <span key={`highlight-${pushIndex}`} className={css.highlightText}>
+        <span key={`highlight-${pushIndex}`} className={css.highlightText} data-text-highlight="">
           {match[0]}
         </span>
       ),