Fix issue #1924, require nostr prefixes start with slash (#1928)

Author: Scroogey-SN

lib/url.js

@@ -93,7 +93,7 @@ export function parseEmbedUrl (href) {
     const { hostname, pathname, searchParams } = new URL(href)
 
     // nostr prefixes: [npub1, nevent1, nprofile1, note1]
-    const nostr = href.match(/(?<id>(?<type>npub1|nevent1|nprofile1|note1|naddr1)[02-9ac-hj-np-z]+)/)
+    const nostr = href.match(/\/(?<id>(?<type>npub1|nevent1|nprofile1|note1|naddr1)[02-9ac-hj-np-z]+)/)
     if (nostr?.groups?.id) {
       let id = nostr.groups.id
       if (nostr.groups.type === 'npub1') {