fix: show bookmarks even when they only have IDs (no content yet)

Root cause: hasContent() was filtering out bookmarks that didn't have content text yet. When we skip event fetching for large collections (>100 IDs), bookmarks only have IDs as placeholders, causing 511/522 bookmarks to be filtered out.

Solution: Updated hasContent() to return true if bookmark has either:
- Valid content (original behavior)
- OR a valid ID (placeholder until events are fetched)

This allows all 522 bookmarks to appear in the sidebar immediately, showing IDs/URLs as placeholders until full event data loads.

Removed debug logging from bookmarkUtils as it served its purpose.

src/utils/bookmarkUtils.tsx

@@ -128,9 +128,12 @@ export function groupIndividualBookmarks(items: IndividualBookmark[]) {
   }
 }
 
-// Simple filter: only exclude bookmarks with empty/whitespace-only content
+// Simple filter: show bookmarks that have content OR just an ID (placeholder)
 export function hasContent(bookmark: IndividualBookmark): boolean {
-  return !!(bookmark.content && bookmark.content.trim().length > 0)
+  // Show if has content OR has an ID (placeholder until events are fetched)
+  const hasValidContent = !!(bookmark.content && bookmark.content.trim().length > 0)
+  const hasId = !!(bookmark.id && bookmark.id.trim().length > 0)
+  return hasValidContent || hasId
 }
 
 // Bookmark sets helpers (kind 30003)