Restore border-b to NoteCard, remove compensating divide-y from containers

The original border-b border-border was removed from NoteCard in 9bd646b
for a photos overlay feature that no longer uses NoteCard. This forced
every container to add divide-y divide-border as a workaround, but
several pages were missed (Bookmarks, Events, Trends, Search, etc).

Restore NoteCard's self-bordering and remove the now-redundant divide-y
wrappers. Existing overrides (EmbeddedNaddr !border-b, Notifications
border-0) continue to work correctly.

src/components/Feed.tsx

@@ -197,7 +197,7 @@ export function Feed({ kinds, tagFilters, header, hideCompose, emptyMessage }: F
             ))}
           </div>
         ) : feedItems.length > 0 ? (
-          <div className="divide-y divide-border">
+          <div>
             {feedItems.map((item: FeedItem) => (
               <NoteCard
                 key={item.repostedBy ? `repost-${item.repostedBy}-${item.event.id}` : item.event.id}

src/components/MusicDetailContent.tsx

@@ -253,7 +253,7 @@ function TrackDetail({ event }: { event: NostrEvent }) {
 
       {/* Comments list */}
       {comments.length > 0 && (
-        <div className="divide-y divide-border">
+        <div>
           {comments.map((comment) => (
             <NoteCard key={comment.id} event={comment} />
           ))}

src/components/NoteCard.tsx

@@ -541,7 +541,7 @@ export function NoteCard({ event, className, repostedBy, compact, threaded, thre
     return (
       <article
         className={cn(
-          'px-4 py-3 hover:bg-secondary/30 transition-colors cursor-pointer overflow-hidden',
+          'px-4 py-3 border-b border-border hover:bg-secondary/30 transition-colors cursor-pointer overflow-hidden',
           className,
         )}
         onClick={handleCardClick}
@@ -622,8 +622,7 @@ export function NoteCard({ event, className, repostedBy, compact, threaded, thre
   return (
     <article
         className={cn(
-          'px-4 py-3 hover:bg-secondary/30 transition-colors cursor-pointer overflow-hidden',
-          (isReply || isComment) && 'border-b border-border',
+          'px-4 py-3 border-b border-border hover:bg-secondary/30 transition-colors cursor-pointer overflow-hidden',
           className,
         )}
         onClick={handleCardClick}

src/components/ThreadedReplyList.tsx

@@ -17,7 +17,7 @@ interface ThreadedReplyListProps {
  */
 export function ThreadedReplyList({ replies }: ThreadedReplyListProps) {
   return (
-    <div className="divide-y divide-border">
+    <div>
       {replies.map(({ reply, firstSubReply }) => (
         <div key={reply.id}>
           <NoteCard event={reply} threaded={!!firstSubReply} />

src/pages/ProfilePage.tsx

@@ -1533,7 +1533,7 @@ export function ProfilePage() {
 
         {/* Pinned posts (only on Posts tab) */}
         {activeTab === 'posts' && pinnedIds.length > 0 && (
-          <div className="divide-y divide-border border-b border-border">
+          <div>
             {pinnedEventsLoading ? (
               pinnedIds.map((id) => (
                 <div key={`pinned-skeleton-${id}`} className="relative">
@@ -1660,7 +1660,7 @@ export function ProfilePage() {
               ))}
             </div>
           ) : currentItems.length > 0 ? (
-            <div className="divide-y divide-border">
+            <div>
               {currentItems.map((item) => (
                 <NoteCard 
                   key={item.repostedBy ? `repost-${item.repostedBy}-${item.event.id}` : item.event.id}