Revert external content share back to kind 1 with i tag

Kind 16 requires an e tag pointing to a Nostr event ID, which external
content doesn't have. Kind 1 with an i tag is the correct approach.

src/hooks/useExternalReactions.ts

@@ -89,7 +89,7 @@ export function useExternalRepostStatus(content: ExternalContent | null | undefi
 
       const events = await nostr.query(
         [{
-          kinds: [16],
+          kinds: [1],
           authors: [user.pubkey],
           '#i': [identifier],
           limit: 1,

src/pages/ExternalContentPage.tsx

@@ -117,20 +117,19 @@ function ExternalActionBar({ content }: { content: ExternalContent }) {
     );
   }, [user, content, identifier, publishEvent, queryClient, toast]);
 
-  // Publish kind 16 generic repost with i tag
+  // Publish kind 1 note sharing the external content via i tag
   const handleShare = useCallback(() => {
     if (!user) return;
     queryClient.setQueryData(['external-user-repost', identifier], 'optimistic');
 
     publishEvent(
       {
-        kind: 16,
-        content: '',
+        kind: 1,
+        content: identifier,
         created_at: Math.floor(Date.now() / 1000),
         tags: [
           ['i', identifier],
           ['k', getExternalKTag(content)],
-          ['alt', `Repost of ${identifier}`],
         ],
       },
       {