fix: dedupe multiple revisions of the same web bookmark

Per an earlier "previously missed" finding: useMyWebBookmarks()
returned every kind-39701 event a relay handed back, but for an
addressable event the pool can return more than one revision of the
same d tag (an edit history, or relays disagreeing on what's
current), which showed up as duplicate rows for the same URL.
Extracted dedupeLatestByDTag() (keeps the newest per d, newest-first)
and covered it with regression tests.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BYiUtZMQeA5RHggQw73wto

src/hooks/useWebBookmarks.test.ts

@@ -1,5 +1,10 @@
 import { describe, expect, it } from 'vitest';
-import { bookmarkDTag, bookmarkUrl } from './useWebBookmarks';
+import type { NostrEvent } from '@nostrify/nostrify';
+import { bookmarkDTag, bookmarkUrl, dedupeLatestByDTag } from './useWebBookmarks';
+
+function bookmarkEvent(dTag: string, createdAt: number, id = `${dTag}-${createdAt}`): NostrEvent {
+  return { id, pubkey: 'author', created_at: createdAt, kind: 39701, tags: [['d', dTag]], content: '', sig: '' };
+}
 
 describe('bookmarkDTag / bookmarkUrl', () => {
   it('strips the https scheme per NIP-B0', () => {
@@ -41,3 +46,30 @@ describe('bookmarkDTag / bookmarkUrl', () => {
     expect(bookmarkUrl('alice.blog:8080/post')).toBe('https://alice.blog:8080/post');
   });
 });
+
+describe('dedupeLatestByDTag', () => {
+  it('keeps only the newest event for each d tag', () => {
+    const older = bookmarkEvent('alice.blog/post', 100);
+    const newer = bookmarkEvent('alice.blog/post', 200);
+    const result = dedupeLatestByDTag([older, newer]);
+    expect(result).toEqual([newer]);
+  });
+
+  it('is order-independent', () => {
+    const older = bookmarkEvent('alice.blog/post', 100);
+    const newer = bookmarkEvent('alice.blog/post', 200);
+    expect(dedupeLatestByDTag([newer, older])).toEqual([newer]);
+  });
+
+  it('keeps distinct d tags separately, sorted newest first', () => {
+    const a = bookmarkEvent('a.com', 100);
+    const b = bookmarkEvent('b.com', 300);
+    const c = bookmarkEvent('c.com', 200);
+    expect(dedupeLatestByDTag([a, b, c])).toEqual([b, c, a]);
+  });
+
+  it('drops events with no d tag', () => {
+    const noD: NostrEvent = { id: 'x', pubkey: 'author', created_at: 0, kind: 39701, tags: [], content: '', sig: '' };
+    expect(dedupeLatestByDTag([noD])).toEqual([]);
+  });
+});

src/hooks/useWebBookmarks.ts

@@ -44,6 +44,22 @@ export interface WebBookmarkInput {
   tags?: string[];
 }
 
+/**
+ * Addressable events: relays across the pool can hand back more than one
+ * revision of the same `d` tag (an edit history, or just multiple relays
+ * disagreeing on what's current). Keeps only the newest per `d`, newest first.
+ */
+export function dedupeLatestByDTag(events: NostrEvent[]): NostrEvent[] {
+  const latest = new Map<string, NostrEvent>();
+  for (const event of events) {
+    const dTag = tagValue(event, 'd');
+    if (!dTag) continue;
+    const current = latest.get(dTag);
+    if (!current || event.created_at > current.created_at) latest.set(dTag, event);
+  }
+  return [...latest.values()].sort((a, b) => b.created_at - a.created_at);
+}
+
 export function useMyWebBookmarks() {
   const { nostr } = useNostr();
   const { user } = useCurrentUser();
@@ -56,9 +72,7 @@ export function useMyWebBookmarks() {
         [{ kinds: [WEB_BOOKMARK_KIND], authors: [user!.pubkey], limit: 200 }],
         { signal: AbortSignal.any([signal, AbortSignal.timeout(6000)]) },
       );
-      return events
-        .filter((event) => Boolean(tagValue(event, 'd')))
-        .sort((a, b) => b.created_at - a.created_at);
+      return dedupeLatestByDTag(events);
     },
     staleTime: 60_000,
   });