avoid search engines following 404ing internal links from descriptions

src/router/video.ts

@@ -55,6 +55,34 @@ app.get('/watch', async ({ query: { v }, set, redirect, error }) => {
       .execute()
   }
 
+  DOMPurify.addHook('afterSanitizeAttributes', function (node) {
+    if (node.tagName === 'A') {
+      const disallowedPatterns: RegExp[] = [
+        /\/playlist/i,
+        /\/hashtag\//i,
+        /\/live\//i,
+        /\/user\//i,
+        /\/shorts\//i,
+        /\/c\//i,
+        /\/@[^\/]/i
+      ];
+      const href = node.getAttribute('href') || '';
+      
+      const shouldConvertToSpan = disallowedPatterns.some(pattern => 
+        pattern.test(href)
+      );
+      
+      if (shouldConvertToSpan) {
+        const span = node.ownerDocument.createElement('span');
+        span.innerHTML = node.innerHTML;
+        if (node.className) span.className = node.className;
+        node.parentNode?.replaceChild(span, node);
+      } else {
+        node.setAttribute('rel', 'nofollow noopener noreferrer');
+      }
+    }
+  })
+
   const html = await m(eta.render('./watch', { 
     transparency,
     ...json,