fix: handle web bookmarks with URLs in d tag and prevent crash

- Extract URL from 'd' tag for kind:39701 web bookmarks
- Add protocol prefix (https://) if missing from web bookmark URLs
- Make classifyUrl handle undefined input gracefully
- Prevent crash when web bookmarks have no content

src/utils/helpers.ts

@@ -13,7 +13,10 @@ export interface UrlClassification {
   buttonText: string
 }
 
-export const classifyUrl = (url: string): UrlClassification => {
+export const classifyUrl = (url: string | undefined): UrlClassification => {
+  if (!url) {
+    return { type: 'article', buttonText: 'READ NOW' }
+  }
   const urlLower = url.toLowerCase()
   
   // Check for YouTube